Start to Add WASM Support Again (#14418)

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# Description
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The [nushell/demo](https://github.com/nushell/demo) project successfully
demonstrated running Nushell in the browser using WASM. However, the
current version of Nushell cannot be easily built for the
`wasm32-unknown-unknown` target, the default for `wasm-bindgen`.

This PR introduces initial support for the `wasm32-unknown-unknown`
target by disabling OS-dependent features such as filesystem access, IO,
and platform/system-specific functionality. This separation is achieved
using a new `os` feature in the following crates:

 - `nu-cmd-lang`
 - `nu-command`
 - `nu-engine`
 - `nu-protocol`

The `os` feature includes all functionality that interacts with an
operating system. It is enabled by default, but can be disabled using
`--no-default-features`. All crates that depend on these core crates now
use `--no-default-features` to allow compilation for WASM.

To demonstrate compatibility, the following script builds all crates
expected to work with WASM. Direct user interaction, running external
commands, working with plugins, and features requiring `openssl` are out
of scope for now due to their complexity or reliance on C libraries,
which are difficult to compile and link in a WASM environment.

```nushell
[ # compatible crates
	"nu-cmd-base",
	"nu-cmd-extra",
	"nu-cmd-lang",
	"nu-color-config",
	"nu-command",
	"nu-derive-value",
	"nu-engine",
	"nu-glob",
	"nu-json",
	"nu-parser",
	"nu-path",
	"nu-pretty-hex",
	"nu-protocol",
	"nu-std",
	"nu-system",
	"nu-table",
	"nu-term-grid",
	"nu-utils",
	"nuon"
] | each {cargo build -p $in --target wasm32-unknown-unknown --no-default-features}
```

## Caveats
This PR has a few caveats:
1. **`miette` and `terminal-size` Dependency Issue**
`miette` depends on `terminal-size`, which uses `rustix` when the target
is not Windows. However, `rustix` requires `std::os::unix`, which is
unavailable in WASM. To address this, I opened a
[PR](https://github.com/eminence/terminal-size/pull/68) for
`terminal-size` to conditionally compile `rustix` only when the target
is Unix. For now, the `Cargo.toml` includes patches to:
    - Use my forked version of `terminal-size`.
- ~~Use an unreleased version of `miette` that depends on
`terminal-size@0.4`.~~

These patches are temporary and can be removed once the upstream changes
are merged and released.

2. **Test Output Adjustments**
Due to the slight bump in the `miette` version, one test required
adjustments to accommodate minor formatting changes in the error output,
such as shifted newlines.

# User-Facing Changes
<!-- List of all changes that impact the user experience here. This
helps us keep track of breaking changes. -->
This shouldn't break anything but allows using some crates for targeting
`wasm32-unknown-unknown` to revive the demo page eventually.

# Tests + Formatting
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- 🟢 `toolkit fmt`
- 🟢 `toolkit clippy`
- 🟢 `toolkit test`
- 🟢 `toolkit test stdlib`

I did not add any extra tests, I just checked that compiling works, also
when using the host target but unselecting the `os` feature.

# After Submitting
<!-- If your PR had any user-facing changes, update [the
documentation](https://github.com/nushell/nushell.github.io) after the
PR is merged, if necessary. This will help us keep the docs up to date.
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~~Breaking the wasm support can be easily done by adding some `use`s or
by adding a new dependency, we should definitely add some CI that also
at least builds against wasm to make sure that building for it keep
working.~~
I added a job to build wasm.

---------

Co-authored-by: Ian Manske <ian.manske@pm.me>

.github/workflows/ci.yml

@@ -162,3 +162,34 @@ jobs:
           else
             echo "no changes in working directory";
           fi
+
+  build-wasm:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4.1.7
+
+      - name: Setup Rust toolchain and cache
+        uses: actions-rust-lang/setup-rust-toolchain@v1.10.1
+
+      - name: Add wasm32-unknown-unknown target
+        run: rustup target add wasm32-unknown-unknown
+
+      - run: cargo build -p nu-cmd-base --no-default-features --target wasm32-unknown-unknown
+      - run: cargo build -p nu-cmd-extra --no-default-features --target wasm32-unknown-unknown
+      - run: cargo build -p nu-cmd-lang --no-default-features --target wasm32-unknown-unknown
+      - run: cargo build -p nu-color-config --no-default-features --target wasm32-unknown-unknown
+      - run: cargo build -p nu-command --no-default-features --target wasm32-unknown-unknown
+      - run: cargo build -p nu-derive-value --no-default-features --target wasm32-unknown-unknown
+      - run: cargo build -p nu-engine --no-default-features --target wasm32-unknown-unknown
+      - run: cargo build -p nu-glob --no-default-features --target wasm32-unknown-unknown
+      - run: cargo build -p nu-json --no-default-features --target wasm32-unknown-unknown
+      - run: cargo build -p nu-parser --no-default-features --target wasm32-unknown-unknown
+      - run: cargo build -p nu-path --no-default-features --target wasm32-unknown-unknown
+      - run: cargo build -p nu-pretty-hex --no-default-features --target wasm32-unknown-unknown
+      - run: cargo build -p nu-protocol --no-default-features --target wasm32-unknown-unknown
+      - run: cargo build -p nu-std --no-default-features --target wasm32-unknown-unknown
+      - run: cargo build -p nu-system --no-default-features --target wasm32-unknown-unknown
+      - run: cargo build -p nu-table --no-default-features --target wasm32-unknown-unknown
+      - run: cargo build -p nu-term-grid --no-default-features --target wasm32-unknown-unknown
+      - run: cargo build -p nu-utils --no-default-features --target wasm32-unknown-unknown
+      - run: cargo build -p nuon --no-default-features --target wasm32-unknown-unknown

Cargo.lock

@@ -2647,7 +2647,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4979f22fdb869068da03c9f7528f8297c6fd2606bc3a4affe42e6a823fdb8da4"
 dependencies = [
  "cfg-if",
- "windows-targets 0.52.6",
+ "windows-targets 0.48.5",
 ]
 
 [[package]]
@@ -3368,6 +3368,7 @@ dependencies = [
  "fancy-regex",
  "filesize",
  "filetime",
+ "getrandom",
  "human-date-parser",
  "indexmap",
  "indicatif",
@@ -3755,6 +3756,7 @@ dependencies = [
 name = "nu-utils"
 version = "0.100.1"
 dependencies = [
+ "crossterm 0.28.1",
  "crossterm_winapi",
  "fancy-regex",
  "log",
@@ -6847,9 +6849,9 @@ dependencies = [
 
 [[package]]
 name = "terminal_size"
-version = "0.4.0"
+version = "0.4.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4f599bd7ca042cfdf8f4512b277c02ba102247820f9d9d4a9f521f496751a6ef"
+checksum = "5352447f921fda68cf61b4101566c0bdb5104eff6804d0678e5227580ab6a4e9"
 dependencies = [
  "rustix",
  "windows-sys 0.59.0",
@@ -7874,7 +7876,7 @@ version = "0.1.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "cf221c93e13a30d793f7645a0e7762c55d169dbb0a49671918a2319d289b10bb"
 dependencies = [
- "windows-sys 0.59.0",
+ "windows-sys 0.48.0",
 ]
 
 [[package]]

Cargo.toml

@@ -134,6 +134,7 @@ quickcheck = "1.0"
 quickcheck_macros = "1.0"
 quote = "1.0"
 rand = "0.8"
+getrandom = "0.2" # pick same version that rand requires
 rand_chacha = "0.3.1"
 ratatui = "0.26"
 rayon = "1.10"

crates/nu-cli/Cargo.toml

@@ -19,11 +19,11 @@ tempfile = { workspace = true }
 
 [dependencies]
 nu-cmd-base = { path = "../nu-cmd-base", version = "0.100.1" }
-nu-engine = { path = "../nu-engine", version = "0.100.1" }
+nu-engine = { path = "../nu-engine", version = "0.100.1", features = ["os"] }
 nu-path = { path = "../nu-path", version = "0.100.1" }
 nu-parser = { path = "../nu-parser", version = "0.100.1" }
 nu-plugin-engine = { path = "../nu-plugin-engine", version = "0.100.1", optional = true }
-nu-protocol = { path = "../nu-protocol", version = "0.100.1" }
+nu-protocol = { path = "../nu-protocol", version = "0.100.1", features = ["os"] }
 nu-utils = { path = "../nu-utils", version = "0.100.1" }
 nu-color-config = { path = "../nu-color-config", version = "0.100.1" }
 nu-ansi-term = { workspace = true }

crates/nu-cmd-base/Cargo.toml

@@ -13,10 +13,10 @@ version = "0.100.1"
 workspace = true
 
 [dependencies]
-nu-engine = { path = "../nu-engine", version = "0.100.1" }
+nu-engine = { path = "../nu-engine", version = "0.100.1", default-features = false }
 nu-parser = { path = "../nu-parser", version = "0.100.1" }
 nu-path = { path = "../nu-path", version = "0.100.1" }
-nu-protocol = { path = "../nu-protocol", version = "0.100.1" }
+nu-protocol = { path = "../nu-protocol", version = "0.100.1", default-features = false }
 
 indexmap = { workspace = true }
 miette = { workspace = true }

crates/nu-cmd-extra/Cargo.toml

@@ -17,12 +17,12 @@ workspace = true
 
 [dependencies]
 nu-cmd-base = { path = "../nu-cmd-base", version = "0.100.1" }
-nu-engine = { path = "../nu-engine", version = "0.100.1" }
+nu-engine = { path = "../nu-engine", version = "0.100.1", default-features = false }
 nu-json = { version = "0.100.1", path = "../nu-json" }
 nu-parser = { path = "../nu-parser", version = "0.100.1" }
 nu-pretty-hex = { version = "0.100.1", path = "../nu-pretty-hex" }
-nu-protocol = { path = "../nu-protocol", version = "0.100.1" }
+nu-protocol = { path = "../nu-protocol", version = "0.100.1", default-features = false }
-nu-utils = { path = "../nu-utils", version = "0.100.1" }
+nu-utils = { path = "../nu-utils", version = "0.100.1", default-features = false }
 
 # Potential dependencies for extras
 heck = { workspace = true }

crates/nu-cmd-lang/Cargo.toml

@@ -15,10 +15,10 @@ bench = false
 workspace = true
 
 [dependencies]
-nu-engine = { path = "../nu-engine", version = "0.100.1" }
+nu-engine = { path = "../nu-engine", version = "0.100.1", default-features = false }
 nu-parser = { path = "../nu-parser", version = "0.100.1" }
-nu-protocol = { path = "../nu-protocol", version = "0.100.1" }
+nu-protocol = { path = "../nu-protocol", version = "0.100.1", default-features = false }
-nu-utils = { path = "../nu-utils", version = "0.100.1" }
+nu-utils = { path = "../nu-utils", version = "0.100.1", default-features = false }
 
 itertools = { workspace = true }
 shadow-rs = { version = "0.36", default-features = false }
@@ -27,6 +27,17 @@ shadow-rs = { version = "0.36", default-features = false }
 shadow-rs = { version = "0.36", default-features = false }
 
 [features]
+default = ["os"]
+os = [
+  "nu-engine/os",
+  "nu-protocol/os",
+  "nu-utils/os",
+]
+plugin = [
+  "nu-protocol/plugin",
+  "os",
+]
+
 mimalloc = []
 trash-support = []
 sqlite = []

crates/nu-cmd-lang/src/core_commands/describe.rs

@@ -169,6 +169,7 @@ fn run(
                 let origin = match stream.source() {
                     ByteStreamSource::Read(_) => "unknown",
                     ByteStreamSource::File(_) => "file",
+                    #[cfg(feature = "os")]
                     ByteStreamSource::Child(_) => "external",
                 };
 

crates/nu-cmd-lang/src/core_commands/do_.rs

@@ -1,9 +1,8 @@
 use nu_engine::{command_prelude::*, get_eval_block_with_early_return, redirect_env};
-use nu_protocol::{
+#[cfg(feature = "os")]
-    engine::Closure,
+use nu_protocol::process::{ChildPipe, ChildProcess};
-    process::{ChildPipe, ChildProcess},
+use nu_protocol::{engine::Closure, ByteStream, ByteStreamSource, OutDest};
-    ByteStream, ByteStreamSource, OutDest,
+
-};
 use std::{
     io::{Cursor, Read},
     thread,
@@ -119,6 +118,13 @@ impl Command for Do {
         match result {
             Ok(PipelineData::ByteStream(stream, metadata)) if capture_errors => {
                 let span = stream.span();
+                #[cfg(not(feature = "os"))]
+                return Err(ShellError::DisabledOsSupport {
+                    msg: "Cannot create a thread to receive stdout message.".to_string(),
+                    span: Some(span),
+                });
+
+                #[cfg(feature = "os")]
                 match stream.into_child() {
                     Ok(mut child) => {
                         // Use a thread to receive stdout message.
@@ -196,6 +202,7 @@ impl Command for Do {
                         OutDest::Pipe | OutDest::PipeSeparate | OutDest::Value
                     ) =>
             {
+                #[cfg(feature = "os")]
                 if let ByteStreamSource::Child(child) = stream.source_mut() {
                     child.ignore_error(true);
                 }

crates/nu-cmd-lang/src/core_commands/ignore.rs

@@ -35,6 +35,7 @@ impl Command for Ignore {
         mut input: PipelineData,
     ) -> Result<PipelineData, ShellError> {
         if let PipelineData::ByteStream(stream, _) = &mut input {
+            #[cfg(feature = "os")]
             if let ByteStreamSource::Child(child) = stream.source_mut() {
                 child.ignore_error(true);
             }

crates/nu-cmd-lang/src/core_commands/version.rs

@@ -116,6 +116,11 @@ pub fn version(engine_state: &EngineState, span: Span) -> Result<PipelineData, S
         Value::string(features_enabled().join(", "), span),
     );
 
+    #[cfg(not(feature = "plugin"))]
+    let _ = engine_state;
+
+    #[cfg(feature = "plugin")]
+    {
         // Get a list of plugin names and versions if present
         let installed_plugins = engine_state
             .plugins()
@@ -134,6 +139,7 @@ pub fn version(engine_state: &EngineState, span: Span) -> Result<PipelineData, S
             "installed_plugins",
             Value::string(installed_plugins.join(", "), span),
         );
+    }
 
     Ok(Value::record(record, span).into_pipeline_data())
 }

crates/nu-cmd-lang/src/lib.rs

@@ -1,3 +1,4 @@
+#![cfg_attr(not(feature = "os"), allow(unused))]
 #![doc = include_str!("../README.md")]
 mod core_commands;
 mod default_context;

crates/nu-color-config/Cargo.toml

@@ -14,8 +14,8 @@ bench = false
 workspace = true
 
 [dependencies]
-nu-protocol = { path = "../nu-protocol", version = "0.100.1" }
+nu-protocol = { path = "../nu-protocol", version = "0.100.1", default-features = false }
-nu-engine = { path = "../nu-engine", version = "0.100.1" }
+nu-engine = { path = "../nu-engine", version = "0.100.1", default-features = false }
 nu-json = { path = "../nu-json", version = "0.100.1" }
 nu-ansi-term = { workspace = true }
 

crates/nu-command/Cargo.toml

@@ -18,17 +18,17 @@ workspace = true
 [dependencies]
 nu-cmd-base = { path = "../nu-cmd-base", version = "0.100.1" }
 nu-color-config = { path = "../nu-color-config", version = "0.100.1" }
-nu-engine = { path = "../nu-engine", version = "0.100.1" }
+nu-engine = { path = "../nu-engine", version = "0.100.1", default-features = false }
 nu-glob = { path = "../nu-glob", version = "0.100.1" }
 nu-json = { path = "../nu-json", version = "0.100.1" }
 nu-parser = { path = "../nu-parser", version = "0.100.1" }
 nu-path = { path = "../nu-path", version = "0.100.1" }
 nu-pretty-hex = { path = "../nu-pretty-hex", version = "0.100.1" }
-nu-protocol = { path = "../nu-protocol", version = "0.100.1" }
+nu-protocol = { path = "../nu-protocol", version = "0.100.1", default-features = false }
 nu-system = { path = "../nu-system", version = "0.100.1" }
 nu-table = { path = "../nu-table", version = "0.100.1" }
 nu-term-grid = { path = "../nu-term-grid", version = "0.100.1" }
-nu-utils = { path = "../nu-utils", version = "0.100.1" }
+nu-utils = { path = "../nu-utils", version = "0.100.1", default-features = false }
 nu-ansi-term = { workspace = true }
 nuon = { path = "../nuon", version = "0.100.1" }
 
@@ -43,7 +43,7 @@ chardetng = { workspace = true }
 chrono = { workspace = true, features = ["std", "unstable-locales", "clock"], default-features = false }
 chrono-humanize = { workspace = true }
 chrono-tz = { workspace = true }
-crossterm = { workspace = true }
+crossterm = { workspace = true, optional = true }
 csv = { workspace = true }
 dialoguer = { workspace = true, default-features = false, features = ["fuzzy-select"] }
 digest = { workspace = true, default-features = false }
@@ -61,19 +61,20 @@ lscolors = { workspace = true, default-features = false, features = ["nu-ansi-te
 md5 = { workspace = true }
 mime = { workspace = true }
 mime_guess = { workspace = true }
-multipart-rs = { workspace = true }
+multipart-rs = { workspace = true, optional = true }
-native-tls = { workspace = true }
+native-tls = { workspace = true, optional = true }
-notify-debouncer-full = { workspace = true, default-features = false }
+notify-debouncer-full = { workspace = true, default-features = false, optional = true }
 num-format = { workspace = true }
 num-traits = { workspace = true }
 oem_cp = { workspace = true }
-open = { workspace = true }
+open = { workspace = true, optional = true }
-os_pipe = { workspace = true }
+os_pipe = { workspace = true, optional = true }
 pathdiff = { workspace = true }
 percent-encoding = { workspace = true }
 print-positions = { workspace = true }
 quick-xml = { workspace = true }
-rand = { workspace = true }
+rand = { workspace = true, optional = true }
+getrandom = { workspace = true, optional = true }
 rayon = { workspace = true }
 regex = { workspace = true }
 roxmltree = { workspace = true }
@@ -89,26 +90,26 @@ tabled = { workspace = true, features = ["ansi"], default-features = false }
 titlecase = { workspace = true }
 toml = { workspace = true, features = ["preserve_order"] }
 unicode-segmentation = { workspace = true }
-ureq = { workspace = true, default-features = false, features = ["charset", "gzip", "json", "native-tls"] }
+ureq = { workspace = true, default-features = false, features = ["charset", "gzip", "json"] }
 url = { workspace = true }
-uu_cp = { workspace = true }
+uu_cp = { workspace = true, optional = true }
-uu_mkdir = { workspace = true }
+uu_mkdir = { workspace = true, optional = true }
-uu_mktemp = { workspace = true }
+uu_mktemp = { workspace = true, optional = true }
-uu_mv = { workspace = true }
+uu_mv = { workspace = true, optional = true }
-uu_touch = { workspace = true }
+uu_touch = { workspace = true, optional = true }
-uu_uname = { workspace = true }
+uu_uname = { workspace = true, optional = true }
-uu_whoami = { workspace = true }
+uu_whoami = { workspace = true, optional = true }
-uuid = { workspace = true, features = ["v4"] }
+uuid = { workspace = true, features = ["v4"], optional = true }
 v_htmlescape = { workspace = true }
 wax = { workspace = true }
-which = { workspace = true }
+which = { workspace = true, optional = true }
 unicode-width = { workspace = true }
 data-encoding = { version = "2.6.0", features = ["alloc"] }
 
 [target.'cfg(windows)'.dependencies]
 winreg = { workspace = true }
 
-[target.'cfg(not(windows))'.dependencies]
+[target.'cfg(all(not(windows), not(target_arch = "wasm32")))'.dependencies]
 uucore = { workspace = true, features = ["mode"] }
 
 [target.'cfg(unix)'.dependencies]
@@ -134,7 +135,53 @@ features = [
 workspace = true
 
 [features]
-plugin = ["nu-parser/plugin"]
+default = ["os"]
+os = [
+	# include other features
+	"js",
+	"network",
+	"nu-protocol/os", 
+	"nu-utils/os",
+
+	# os-dependant dependencies
+	"crossterm",
+	"notify-debouncer-full",
+	"open",
+	"os_pipe",
+	"uu_cp",
+	"uu_mkdir",
+	"uu_mktemp",
+	"uu_mv",
+	"uu_touch",
+	"uu_uname",
+	"uu_whoami",
+	"which",
+]
+
+# The dependencies listed below need 'getrandom'. 
+# They work with JS (usually with wasm-bindgen) or regular OS support. 
+# Hence they are also put under the 'os' feature to avoid repetition.
+js = [
+	"getrandom", 
+	"getrandom/js", 
+	"rand", 
+	"uuid",
+]
+
+# These dependencies require networking capabilities, especially the http
+# interface requires openssl which is not easy to embed into wasm,
+# using rustls could solve this issue.
+network = [
+	"multipart-rs", 
+	"native-tls",
+	"ureq/native-tls",
+	"uuid",
+]
+
+plugin = [
+	"nu-parser/plugin",
+	"os", 
+]
 sqlite = ["rusqlite"]
 trash-support = ["trash"]
 

crates/nu-command/src/debug/info.rs

@@ -177,4 +177,9 @@ fn get_thread_id() -> u64 {
     {
         nix::sys::pthread::pthread_self() as u64
     }
+    #[cfg(target_arch = "wasm32")]
+    {
+        // wasm doesn't have any threads accessible, so we return 0 as a fallback
+        0
+    }
 }

crates/nu-command/src/debug/inspect.rs

@@ -1,6 +1,6 @@
 use super::inspect_table;
-use crossterm::terminal::size;
 use nu_engine::command_prelude::*;
+use nu_utils::terminal_size;
 
 #[derive(Clone)]
 pub struct Inspect;
@@ -38,7 +38,7 @@ impl Command for Inspect {
         let original_input = input_val.clone();
         let description = input_val.get_type().to_string();
 
-        let (cols, _rows) = size().unwrap_or((0, 0));
+        let (cols, _rows) = terminal_size().unwrap_or((0, 0));
 
         let table = inspect_table::build_table(input_val, description, cols as usize);
 

crates/nu-command/src/default_context.rs

@@ -27,6 +27,10 @@ pub fn add_shell_command_context(mut engine_state: EngineState) -> EngineState {
         }
 
         // Filters
+        #[cfg(feature = "rand")]
+        bind_command! {
+            Shuffle
+        }
         bind_command! {
             All,
             Any,
@@ -72,7 +76,6 @@ pub fn add_shell_command_context(mut engine_state: EngineState) -> EngineState {
             Rename,
             Reverse,
             Select,
-            Shuffle,
             Skip,
             SkipUntil,
             SkipWhile,
@@ -114,6 +117,7 @@ pub fn add_shell_command_context(mut engine_state: EngineState) -> EngineState {
         };
 
         // System
+        #[cfg(feature = "os")]
         bind_command! {
             Complete,
             External,
@@ -161,10 +165,12 @@ pub fn add_shell_command_context(mut engine_state: EngineState) -> EngineState {
             ViewSpan,
         };
 
-        #[cfg(windows)]
+        #[cfg(all(feature = "os", windows))]
         bind_command! { RegistryQuery }
 
-        #[cfg(any(
+        #[cfg(all(
+            feature = "os",
+            any(
                 target_os = "android",
                 target_os = "linux",
                 target_os = "freebsd",
@@ -172,6 +178,7 @@ pub fn add_shell_command_context(mut engine_state: EngineState) -> EngineState {
                 target_os = "openbsd",
                 target_os = "macos",
                 target_os = "windows"
+            )
         ))]
         bind_command! { Ps };
 
@@ -219,6 +226,7 @@ pub fn add_shell_command_context(mut engine_state: EngineState) -> EngineState {
         };
 
         // FileSystem
+        #[cfg(feature = "os")]
         bind_command! {
             Cd,
             Ls,
@@ -237,6 +245,7 @@ pub fn add_shell_command_context(mut engine_state: EngineState) -> EngineState {
         };
 
         // Platform
+        #[cfg(feature = "os")]
         bind_command! {
             Ansi,
             AnsiLink,
@@ -255,7 +264,7 @@ pub fn add_shell_command_context(mut engine_state: EngineState) -> EngineState {
             Whoami,
         };
 
-        #[cfg(unix)]
+        #[cfg(all(unix, feature = "os"))]
         bind_command! { ULimit };
 
         // Date
@@ -380,6 +389,7 @@ pub fn add_shell_command_context(mut engine_state: EngineState) -> EngineState {
         }
 
         // Network
+        #[cfg(feature = "network")]
         bind_command! {
             Http,
             HttpDelete,
@@ -389,6 +399,9 @@ pub fn add_shell_command_context(mut engine_state: EngineState) -> EngineState {
             HttpPost,
             HttpPut,
             HttpOptions,
+            Port,
+        }
+        bind_command! {
             Url,
             UrlBuildQuery,
             UrlSplitQuery,
@@ -396,10 +409,10 @@ pub fn add_shell_command_context(mut engine_state: EngineState) -> EngineState {
             UrlEncode,
             UrlJoin,
             UrlParse,
-            Port,
         }
 
         // Random
+        #[cfg(feature = "rand")]
         bind_command! {
             Random,
             RandomBool,

crates/nu-command/src/env/config/config_.rs

@@ -1,4 +1,6 @@
-use nu_engine::{command_prelude::*, get_full_help};
+use nu_cmd_base::util::get_editor;
+use nu_engine::{command_prelude::*, env_to_strings, get_full_help};
+use nu_system::ForegroundChild;
 
 #[derive(Clone)]
 pub struct ConfigMeta;
@@ -36,3 +38,79 @@ impl Command for ConfigMeta {
         vec!["options", "setup"]
     }
 }
+
+#[cfg(not(feature = "os"))]
+pub(super) fn start_editor(
+    _: &'static str,
+    _: &EngineState,
+    _: &mut Stack,
+    call: &Call,
+) -> Result<PipelineData, ShellError> {
+    Err(ShellError::DisabledOsSupport {
+        msg: "Running external commands is not available without OS support.".to_string(),
+        span: Some(call.head),
+    })
+}
+
+#[cfg(feature = "os")]
+pub(super) fn start_editor(
+    config_path: &'static str,
+    engine_state: &EngineState,
+    stack: &mut Stack,
+    call: &Call,
+) -> Result<PipelineData, ShellError> {
+    // Find the editor executable.
+    let (editor_name, editor_args) = get_editor(engine_state, stack, call.head)?;
+    let paths = nu_engine::env::path_str(engine_state, stack, call.head)?;
+    let cwd = engine_state.cwd(Some(stack))?;
+    let editor_executable =
+        crate::which(&editor_name, &paths, cwd.as_ref()).ok_or(ShellError::ExternalCommand {
+            label: format!("`{editor_name}` not found"),
+            help: "Failed to find the editor executable".into(),
+            span: call.head,
+        })?;
+
+    let Some(config_path) = engine_state.get_config_path(config_path) else {
+        return Err(ShellError::GenericError {
+            error: format!("Could not find $nu.{config_path}"),
+            msg: format!("Could not find $nu.{config_path}"),
+            span: None,
+            help: None,
+            inner: vec![],
+        });
+    };
+    let config_path = config_path.to_string_lossy().to_string();
+
+    // Create the command.
+    let mut command = std::process::Command::new(editor_executable);
+
+    // Configure PWD.
+    command.current_dir(cwd);
+
+    // Configure environment variables.
+    let envs = env_to_strings(engine_state, stack)?;
+    command.env_clear();
+    command.envs(envs);
+
+    // Configure args.
+    command.arg(config_path);
+    command.args(editor_args);
+
+    // Spawn the child process. On Unix, also put the child process to
+    // foreground if we're in an interactive session.
+    #[cfg(windows)]
+    let child = ForegroundChild::spawn(command)?;
+    #[cfg(unix)]
+    let child = ForegroundChild::spawn(
+        command,
+        engine_state.is_interactive,
+        &engine_state.pipeline_externals_state,
+    )?;
+
+    // Wrap the output into a `PipelineData::ByteStream`.
+    let child = nu_protocol::process::ChildProcess::new(child, None, false, call.head)?;
+    Ok(PipelineData::ByteStream(
+        ByteStream::child(child, call.head),
+        None,
+    ))
+}

crates/nu-command/src/env/config/config_env.rs

@@ -1,7 +1,4 @@
-use nu_cmd_base::util::get_editor;
+use nu_engine::command_prelude::*;
-use nu_engine::{command_prelude::*, env_to_strings};
-use nu_protocol::{process::ChildProcess, ByteStream};
-use nu_system::ForegroundChild;
 
 #[derive(Clone)]
 pub struct ConfigEnv;
@@ -81,60 +78,6 @@ impl Command for ConfigEnv {
             return Ok(Value::string(nu_utils::get_sample_env(), head).into_pipeline_data());
         }
 
-        // Find the editor executable.
+        super::config_::start_editor("env-path", engine_state, stack, call)
-        let (editor_name, editor_args) = get_editor(engine_state, stack, call.head)?;
-        let paths = nu_engine::env::path_str(engine_state, stack, call.head)?;
-        let cwd = engine_state.cwd(Some(stack))?;
-        let editor_executable = crate::which(&editor_name, &paths, cwd.as_ref()).ok_or(
-            ShellError::ExternalCommand {
-                label: format!("`{editor_name}` not found"),
-                help: "Failed to find the editor executable".into(),
-                span: call.head,
-            },
-        )?;
-
-        let Some(env_path) = engine_state.get_config_path("env-path") else {
-            return Err(ShellError::GenericError {
-                error: "Could not find $nu.env-path".into(),
-                msg: "Could not find $nu.env-path".into(),
-                span: None,
-                help: None,
-                inner: vec![],
-            });
-        };
-        let env_path = env_path.to_string_lossy().to_string();
-
-        // Create the command.
-        let mut command = std::process::Command::new(editor_executable);
-
-        // Configure PWD.
-        command.current_dir(cwd);
-
-        // Configure environment variables.
-        let envs = env_to_strings(engine_state, stack)?;
-        command.env_clear();
-        command.envs(envs);
-
-        // Configure args.
-        command.arg(env_path);
-        command.args(editor_args);
-
-        // Spawn the child process. On Unix, also put the child process to
-        // foreground if we're in an interactive session.
-        #[cfg(windows)]
-        let child = ForegroundChild::spawn(command)?;
-        #[cfg(unix)]
-        let child = ForegroundChild::spawn(
-            command,
-            engine_state.is_interactive,
-            &engine_state.pipeline_externals_state,
-        )?;
-
-        // Wrap the output into a `PipelineData::ByteStream`.
-        let child = ChildProcess::new(child, None, false, call.head)?;
-        Ok(PipelineData::ByteStream(
-            ByteStream::child(child, call.head),
-            None,
-        ))
     }
 }

crates/nu-command/src/env/config/config_nu.rs

@@ -1,7 +1,4 @@
-use nu_cmd_base::util::get_editor;
+use nu_engine::command_prelude::*;
-use nu_engine::{command_prelude::*, env_to_strings};
-use nu_protocol::{process::ChildProcess, ByteStream};
-use nu_system::ForegroundChild;
 
 #[derive(Clone)]
 pub struct ConfigNu;
@@ -83,60 +80,6 @@ impl Command for ConfigNu {
             return Ok(Value::string(nu_utils::get_sample_config(), head).into_pipeline_data());
         }
 
-        // Find the editor executable.
+        super::config_::start_editor("config-path", engine_state, stack, call)
-        let (editor_name, editor_args) = get_editor(engine_state, stack, call.head)?;
-        let paths = nu_engine::env::path_str(engine_state, stack, call.head)?;
-        let cwd = engine_state.cwd(Some(stack))?;
-        let editor_executable = crate::which(&editor_name, &paths, cwd.as_ref()).ok_or(
-            ShellError::ExternalCommand {
-                label: format!("`{editor_name}` not found"),
-                help: "Failed to find the editor executable".into(),
-                span: call.head,
-            },
-        )?;
-
-        let Some(config_path) = engine_state.get_config_path("config-path") else {
-            return Err(ShellError::GenericError {
-                error: "Could not find $nu.config-path".into(),
-                msg: "Could not find $nu.config-path".into(),
-                span: None,
-                help: None,
-                inner: vec![],
-            });
-        };
-        let config_path = config_path.to_string_lossy().to_string();
-
-        // Create the command.
-        let mut command = std::process::Command::new(editor_executable);
-
-        // Configure PWD.
-        command.current_dir(cwd);
-
-        // Configure environment variables.
-        let envs = env_to_strings(engine_state, stack)?;
-        command.env_clear();
-        command.envs(envs);
-
-        // Configure args.
-        command.arg(config_path);
-        command.args(editor_args);
-
-        // Spawn the child process. On Unix, also put the child process to
-        // foreground if we're in an interactive session.
-        #[cfg(windows)]
-        let child = ForegroundChild::spawn(command)?;
-        #[cfg(unix)]
-        let child = ForegroundChild::spawn(
-            command,
-            engine_state.is_interactive,
-            &engine_state.pipeline_externals_state,
-        )?;
-
-        // Wrap the output into a `PipelineData::ByteStream`.
-        let child = ChildProcess::new(child, None, false, call.head)?;
-        Ok(PipelineData::ByteStream(
-            ByteStream::child(child, call.head),
-            None,
-        ))
     }
 }

crates/nu-command/src/experimental/is_admin.rs

@@ -103,3 +103,9 @@ fn is_root_impl() -> bool {
 
     elevated
 }
+
+#[cfg(target_arch = "wasm32")]
+fn is_root_impl() -> bool {
+    // in wasm we don't have a user system, so technically we are never root
+    false
+}

crates/nu-command/src/filesystem/save.rs

@@ -102,6 +102,7 @@ impl Command for Save {
                     ByteStreamSource::File(source) => {
                         stream_to_file(source, size, signals, file, span, progress)?;
                     }
+                    #[cfg(feature = "os")]
                     ByteStreamSource::Child(mut child) => {
                         fn write_or_consume_stderr(
                             stderr: ChildPipe,

crates/nu-command/src/filters/mod.rs

@@ -37,6 +37,7 @@ mod reject;
 mod rename;
 mod reverse;
 mod select;
+#[cfg(feature = "rand")]
 mod shuffle;
 mod skip;
 mod sort;
@@ -95,6 +96,7 @@ pub use reject::Reject;
 pub use rename::Rename;
 pub use reverse::Reverse;
 pub use select::Select;
+#[cfg(feature = "rand")]
 pub use shuffle::Shuffle;
 pub use skip::*;
 pub use sort::Sort;

crates/nu-command/src/filters/tee.rs

@@ -1,7 +1,9 @@
 use nu_engine::{command_prelude::*, get_eval_block_with_early_return};
+#[cfg(feature = "os")]
+use nu_protocol::process::ChildPipe;
 use nu_protocol::{
-    byte_stream::copy_with_signals, engine::Closure, process::ChildPipe, report_shell_error,
+    byte_stream::copy_with_signals, engine::Closure, report_shell_error, ByteStream,
-    ByteStream, ByteStreamSource, OutDest, PipelineMetadata, Signals,
+    ByteStreamSource, OutDest, PipelineMetadata, Signals,
 };
 use std::{
     io::{self, Read, Write},
@@ -152,6 +154,7 @@ use it in your pipeline."#
                         metadata,
                     ))
                 }
+                #[cfg(feature = "os")]
                 ByteStreamSource::Child(mut child) => {
                     let stderr_thread = if use_stderr {
                         let stderr_thread = if let Some(stderr) = child.stderr.take() {
@@ -454,6 +457,7 @@ fn copy(src: impl Read, dest: impl Write, info: &StreamInfo) -> Result<(), Shell
     Ok(())
 }
 
+#[cfg(feature = "os")]
 fn copy_pipe(pipe: ChildPipe, dest: impl Write, info: &StreamInfo) -> Result<(), ShellError> {
     match pipe {
         ChildPipe::Pipe(pipe) => copy(pipe, dest, info),
@@ -477,6 +481,7 @@ fn copy_on_thread(
         .map_err(|e| e.into_spanned(span).into())
 }
 
+#[cfg(feature = "os")]
 fn copy_pipe_on_thread(
     pipe: ChildPipe,
     dest: impl Write + Send + 'static,

crates/nu-command/src/lib.rs

@@ -1,3 +1,4 @@
+#![cfg_attr(not(feature = "os"), allow(unused))]
 #![doc = include_str!("../README.md")]
 mod bytes;
 mod charting;
@@ -8,6 +9,7 @@ mod default_context;
 mod env;
 mod example_test;
 mod experimental;
+#[cfg(feature = "os")]
 mod filesystem;
 mod filters;
 mod formats;
@@ -18,8 +20,10 @@ mod math;
 mod misc;
 mod network;
 mod path;
+#[cfg(feature = "os")]
 mod platform;
 mod progress_bar;
+#[cfg(feature = "rand")]
 mod random;
 mod removed;
 mod shells;
@@ -27,6 +31,7 @@ mod sort_utils;
 #[cfg(feature = "sqlite")]
 mod stor;
 mod strings;
+#[cfg(feature = "os")]
 mod system;
 mod viewers;
 
@@ -40,6 +45,7 @@ pub use env::*;
 #[cfg(test)]
 pub use example_test::{test_examples, test_examples_with_commands};
 pub use experimental::*;
+#[cfg(feature = "os")]
 pub use filesystem::*;
 pub use filters::*;
 pub use formats::*;
@@ -50,7 +56,9 @@ pub use math::*;
 pub use misc::*;
 pub use network::*;
 pub use path::*;
+#[cfg(feature = "os")]
 pub use platform::*;
+#[cfg(feature = "rand")]
 pub use random::*;
 pub use removed::*;
 pub use shells::*;
@@ -58,6 +66,7 @@ pub use sort_utils::*;
 #[cfg(feature = "sqlite")]
 pub use stor::*;
 pub use strings::*;
+#[cfg(feature = "os")]
 pub use system::*;
 pub use viewers::*;
 

crates/nu-command/src/network/mod.rs

@@ -1,8 +1,12 @@
+#[cfg(feature = "network")]
 mod http;
+#[cfg(feature = "network")]
 mod port;
 mod url;
 
+#[cfg(feature = "network")]
 pub use self::http::*;
 pub use self::url::*;
 
+#[cfg(feature = "network")]
 pub use port::SubCommand as Port;

crates/nu-command/src/viewers/griddle.rs

@@ -1,11 +1,10 @@
 // use super::icons::{icon_for_file, iconify_style_ansi_to_nu};
 use super::icons::icon_for_file;
-use crossterm::terminal::size;
 use lscolors::Style;
 use nu_engine::{command_prelude::*, env_to_string};
 use nu_protocol::Config;
 use nu_term_grid::grid::{Alignment, Cell, Direction, Filling, Grid, GridOptions};
-use nu_utils::get_ls_colors;
+use nu_utils::{get_ls_colors, terminal_size};
 use std::path::Path;
 
 #[derive(Clone)]
@@ -192,7 +191,7 @@ fn create_grid_output(
 
     let cols = if let Some(col) = width_param {
         col as u16
-    } else if let Ok((w, _h)) = size() {
+    } else if let Ok((w, _h)) = terminal_size() {
         w
     } else {
         80u16

crates/nu-command/src/viewers/table.rs

@@ -2,7 +2,6 @@
 //        overall reduce the redundant calls to StyleComputer etc.
 //        the goal is to configure it once...
 
-use crossterm::terminal::size;
 use lscolors::{LsColors, Style};
 use nu_color_config::{color_from_hex, StyleComputer, TextStyle};
 use nu_engine::{command_prelude::*, env_to_string};
@@ -15,7 +14,7 @@ use nu_table::{
     common::create_nu_table_config, CollapsedTable, ExpandedTable, JustTable, NuTable, NuTableCell,
     StringResult, TableOpts, TableOutput,
 };
-use nu_utils::get_ls_colors;
+use nu_utils::{get_ls_colors, terminal_size};
 use std::{
     collections::VecDeque,
     io::{IsTerminal, Read},
@@ -30,7 +29,7 @@ const STREAM_PAGE_SIZE: usize = 1000;
 fn get_width_param(width_param: Option<i64>) -> usize {
     if let Some(col) = width_param {
         col as usize
-    } else if let Ok((w, _h)) = size() {
+    } else if let Ok((w, _h)) = terminal_size() {
         w as usize
     } else {
         80
@@ -712,6 +711,13 @@ fn make_clickable_link(
 ) -> String {
     // uri's based on this https://gist.github.com/egmontkob/eb114294efbcd5adb1944c9f3cb5feda
 
+    #[cfg(any(
+        unix,
+        windows,
+        target_os = "redox",
+        target_os = "wasi",
+        target_os = "hermit"
+    ))]
     if show_clickable_links {
         format!(
             "\x1b]8;;{}\x1b\\{}\x1b]8;;\x1b\\",
@@ -727,6 +733,18 @@ fn make_clickable_link(
             None => full_path,
         }
     }
+
+    #[cfg(not(any(
+        unix,
+        windows,
+        target_os = "redox",
+        target_os = "wasi",
+        target_os = "hermit"
+    )))]
+    match link_name {
+        Some(link_name) => link_name.to_string(),
+        None => full_path,
+    }
 }
 
 struct PagingTableCreator {

crates/nu-engine/Cargo.toml

@@ -14,12 +14,20 @@ bench = false
 workspace = true
 
 [dependencies]
-nu-protocol = { path = "../nu-protocol", features = ["plugin"], version = "0.100.1" }
+nu-protocol = { path = "../nu-protocol", version = "0.100.1", default-features = false }
 nu-path = { path = "../nu-path", version = "0.100.1" }
 nu-glob = { path = "../nu-glob", version = "0.100.1" }
-nu-utils = { path = "../nu-utils", version = "0.100.1" }
+nu-utils = { path = "../nu-utils", version = "0.100.1", default-features = false }
 log = { workspace = true }
 terminal_size = { workspace = true }
 
 [features]
-plugin = []
+default = ["os"]
+os = [
+  "nu-protocol/os",
+  "nu-utils/os",
+]
+plugin = [
+  "nu-protocol/plugin",
+  "os",
+]

crates/nu-engine/src/eval_ir.rs

@@ -8,9 +8,9 @@ use nu_protocol::{
         Argument, Closure, EngineState, ErrorHandler, Matcher, Redirection, Stack, StateWorkingSet,
     },
     ir::{Call, DataSlice, Instruction, IrAstRef, IrBlock, Literal, RedirectMode},
-    ByteStreamSource, DataSource, DeclId, ErrSpan, Flag, IntoPipelineData, IntoSpanned, ListStream,
+    DataSource, DeclId, ErrSpan, Flag, IntoPipelineData, IntoSpanned, ListStream, OutDest,
-    OutDest, PipelineData, PipelineMetadata, PositionalArg, Range, Record, RegId, ShellError,
+    PipelineData, PipelineMetadata, PositionalArg, Range, Record, RegId, ShellError, Signals,
-    Signals, Signature, Span, Spanned, Type, Value, VarId, ENV_VARIABLE_ID,
+    Signature, Span, Spanned, Type, Value, VarId, ENV_VARIABLE_ID,
 };
 use nu_utils::IgnoreCaseExt;
 
@@ -478,8 +478,9 @@ fn eval_instruction<D: DebugContext>(
             Ok(Continue)
         }
         Instruction::CheckErrRedirected { src } => match ctx.borrow_reg(*src) {
+            #[cfg(feature = "os")]
             PipelineData::ByteStream(stream, _)
-                if matches!(stream.source(), ByteStreamSource::Child(_)) =>
+                if matches!(stream.source(), nu_protocol::ByteStreamSource::Child(_)) =>
             {
                 Ok(Continue)
             }
@@ -513,7 +514,7 @@ fn eval_instruction<D: DebugContext>(
                     span: Some(*span),
                 })?;
             let is_external = if let PipelineData::ByteStream(stream, ..) = &src {
-                matches!(stream.source(), ByteStreamSource::Child(..))
+                stream.source().is_external()
             } else {
                 false
             };

crates/nu-parser/Cargo.toml

@@ -15,11 +15,11 @@ bench = false
 workspace = true
 
 [dependencies]
-nu-engine = { path = "../nu-engine", version = "0.100.1" }
+nu-engine = { path = "../nu-engine", version = "0.100.1", default-features = false }
 nu-path = { path = "../nu-path", version = "0.100.1" }
 nu-plugin-engine = { path = "../nu-plugin-engine", optional = true, version = "0.100.1" }
-nu-protocol = { path = "../nu-protocol", version = "0.100.1" }
+nu-protocol = { path = "../nu-protocol", version = "0.100.1", default-features = false }
-nu-utils = { path = "../nu-utils", version = "0.100.1" }
+nu-utils = { path = "../nu-utils", version = "0.100.1", default-features = false }
 
 bytesize = { workspace = true }
 chrono = { default-features = false, features = ['std'], workspace = true }

crates/nu-path/src/tilde.rs

@@ -60,6 +60,7 @@ fn expand_tilde_with_home(path: impl AsRef<Path>, home: Option<PathBuf>) -> Path
     }
 }
 
+#[cfg(not(target_arch = "wasm32"))]
 fn fallback_home_dir(username: &str) -> PathBuf {
     PathBuf::from_iter([FALLBACK_USER_HOME_BASE_DIR, username])
 }
@@ -110,6 +111,13 @@ fn user_home_dir(username: &str) -> PathBuf {
     }
 }
 
+#[cfg(target_arch = "wasm32")]
+fn user_home_dir(_: &str) -> PathBuf {
+    // if WASI is used, we try to get a home dir via HOME env, otherwise we don't have a home dir
+    let home = std::env::var("HOME").unwrap_or_else(|_| "/".to_string());
+    PathBuf::from(home)
+}
+
 /// Returns true if the shell is running inside the Termux terminal emulator
 /// app.
 #[cfg(target_os = "android")]

crates/nu-path/src/trailing_slash.rs

@@ -36,6 +36,13 @@ pub fn has_trailing_slash(path: &Path) -> bool {
     last == Some(&b'/')
 }
 
+/// `true` if the path has a trailing slash, including if it's the root directory.
+#[cfg(target_arch = "wasm32")]
+pub fn has_trailing_slash(path: &Path) -> bool {
+    // in the web paths are often just URLs, they are separated by forward slashes
+    path.to_str().map_or(false, |s| s.ends_with('/'))
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;

crates/nu-plugin/Cargo.toml

@@ -14,8 +14,8 @@ bench = false
 workspace = true
 
 [dependencies]
-nu-engine = { path = "../nu-engine", version = "0.100.1" }
+nu-engine = { path = "../nu-engine", version = "0.100.1", features = ["plugin"] }
-nu-protocol = { path = "../nu-protocol", version = "0.100.1" }
+nu-protocol = { path = "../nu-protocol", version = "0.100.1", features = ["plugin"] }
 nu-plugin-protocol = { path = "../nu-plugin-protocol", version = "0.100.1" }
 nu-plugin-core = { path = "../nu-plugin-core", version = "0.100.1", default-features = false }
 nu-utils = { path = "../nu-utils", version = "0.100.1" }

crates/nu-protocol/Cargo.toml

@@ -16,7 +16,7 @@ bench = false
 workspace = true
 
 [dependencies]
-nu-utils = { path = "../nu-utils", version = "0.100.1" }
+nu-utils = { path = "../nu-utils", version = "0.100.1", default-features = false }
 nu-path = { path = "../nu-path", version = "0.100.1" }
 nu-system = { path = "../nu-system", version = "0.100.1" }
 nu-derive-value = { path = "../nu-derive-value", version = "0.100.1" }
@@ -38,7 +38,7 @@ serde = { workspace = true }
 serde_json = { workspace = true }
 thiserror = "2.0"
 typetag = "0.2"
-os_pipe = { workspace = true, features = ["io_safety"] }
+os_pipe = { workspace = true, optional = true, features = ["io_safety"] }
 log = { workspace = true }
 
 [target.'cfg(unix)'.dependencies]
@@ -49,8 +49,15 @@ dirs-sys = { workspace = true }
 windows-sys = { workspace = true }
 
 [features]
+default = ["os"]
+os = [
+  "nu-utils/os",
+  "os_pipe",
+]
+
 plugin = [
   "brotli",
+  "os",
   "rmp-serde",
 ]
 

crates/nu-protocol/src/errors/shell_error.rs

@@ -1458,6 +1458,17 @@ On Windows, this would be %USERPROFILE%\AppData\Roaming"#
         #[label = "while running this code"]
         span: Option<Span>,
     },
+
+    #[error("OS feature is disabled: {msg}")]
+    #[diagnostic(
+        code(nu::shell::os_disabled),
+        help("You're probably running outside an OS like a browser, we cannot support this")
+    )]
+    DisabledOsSupport {
+        msg: String,
+        #[label = "while running this code"]
+        span: Option<Span>,
+    },
 }
 
 impl ShellError {

crates/nu-protocol/src/lib.rs

@@ -1,3 +1,4 @@
+#![cfg_attr(not(feature = "os"), allow(unused))]
 #![doc = include_str!("../README.md")]
 mod alias;
 pub mod ast;
@@ -17,6 +18,7 @@ pub mod parser_path;
 mod pipeline;
 #[cfg(feature = "plugin")]
 mod plugin;
+#[cfg(feature = "os")]
 pub mod process;
 mod signature;
 pub mod span;

crates/nu-protocol/src/pipeline/byte_stream.rs

@@ -1,8 +1,7 @@
 //! Module managing the streaming of raw bytes between pipeline elements
-use crate::{
+#[cfg(feature = "os")]
-    process::{ChildPipe, ChildProcess},
+use crate::process::{ChildPipe, ChildProcess};
-    ErrSpan, IntoSpanned, PipelineData, ShellError, Signals, Span, Type, Value,
+use crate::{ErrSpan, IntoSpanned, PipelineData, ShellError, Signals, Span, Type, Value};
-};
 use serde::{Deserialize, Serialize};
 #[cfg(unix)]
 use std::os::fd::OwnedFd;
@@ -24,6 +23,7 @@ use std::{
 pub enum ByteStreamSource {
     Read(Box<dyn Read + Send + 'static>),
     File(File),
+    #[cfg(feature = "os")]
     Child(Box<ChildProcess>),
 }
 
@@ -32,6 +32,7 @@ impl ByteStreamSource {
         match self {
             ByteStreamSource::Read(read) => Some(SourceReader::Read(read)),
             ByteStreamSource::File(file) => Some(SourceReader::File(file)),
+            #[cfg(feature = "os")]
             ByteStreamSource::Child(mut child) => child.stdout.take().map(|stdout| match stdout {
                 ChildPipe::Pipe(pipe) => SourceReader::File(convert_file(pipe)),
                 ChildPipe::Tee(tee) => SourceReader::Read(tee),
@@ -40,9 +41,16 @@ impl ByteStreamSource {
     }
 
     /// Source is a `Child` or `File`, rather than `Read`. Currently affects trimming
-    fn is_external(&self) -> bool {
+    #[cfg(feature = "os")]
+    pub fn is_external(&self) -> bool {
         matches!(self, ByteStreamSource::Child(..))
     }
+
+    #[cfg(not(feature = "os"))]
+    pub fn is_external(&self) -> bool {
+        // without os support we never have externals
+        false
+    }
 }
 
 impl Debug for ByteStreamSource {
@@ -50,6 +58,7 @@ impl Debug for ByteStreamSource {
         match self {
             ByteStreamSource::Read(_) => f.debug_tuple("Read").field(&"..").finish(),
             ByteStreamSource::File(file) => f.debug_tuple("File").field(file).finish(),
+            #[cfg(feature = "os")]
             ByteStreamSource::Child(child) => f.debug_tuple("Child").field(child).finish(),
         }
     }
@@ -247,6 +256,7 @@ impl ByteStream {
     ///
     /// The type is implicitly `Unknown`, as it's not typically known whether child processes will
     /// return text or binary.
+    #[cfg(feature = "os")]
     pub fn child(child: ChildProcess, span: Span) -> Self {
         Self::new(
             ByteStreamSource::Child(Box::new(child)),
@@ -260,6 +270,7 @@ impl ByteStream {
     ///
     /// The type is implicitly `Unknown`, as it's not typically known whether stdin is text or
     /// binary.
+    #[cfg(feature = "os")]
     pub fn stdin(span: Span) -> Result<Self, ShellError> {
         let stdin = os_pipe::dup_stdin().err_span(span)?;
         let source = ByteStreamSource::File(convert_file(stdin));
@@ -271,6 +282,14 @@ impl ByteStream {
         ))
     }
 
+    #[cfg(not(feature = "os"))]
+    pub fn stdin(span: Span) -> Result<Self, ShellError> {
+        Err(ShellError::DisabledOsSupport {
+            msg: "Stdin is not supported".to_string(),
+            span: Some(span),
+        })
+    }
+
     /// Create a [`ByteStream`] from a generator function that writes data to the given buffer
     /// when called, and returns `Ok(false)` on end of stream.
     pub fn from_fn(
@@ -432,6 +451,7 @@ impl ByteStream {
         match self.stream {
             ByteStreamSource::Read(..) => Err(self),
             ByteStreamSource::File(file) => Ok(file.into()),
+            #[cfg(feature = "os")]
             ByteStreamSource::Child(child) => {
                 if let ChildProcess {
                     stdout: Some(ChildPipe::Pipe(stdout)),
@@ -453,6 +473,7 @@ impl ByteStream {
     ///
     /// This will only succeed if the [`ByteStreamSource`] of the [`ByteStream`] is [`Child`](ByteStreamSource::Child).
     /// All other cases return an `Err` with the original [`ByteStream`] in it.
+    #[cfg(feature = "os")]
     pub fn into_child(self) -> Result<ChildProcess, Self> {
         if let ByteStreamSource::Child(child) = self.stream {
             Ok(*child)
@@ -477,6 +498,7 @@ impl ByteStream {
                 file.read_to_end(&mut buf).err_span(self.span)?;
                 Ok(buf)
             }
+            #[cfg(feature = "os")]
             ByteStreamSource::Child(child) => child.into_bytes(),
         }
     }
@@ -551,6 +573,7 @@ impl ByteStream {
                 Ok(())
             }
             ByteStreamSource::File(_) => Ok(()),
+            #[cfg(feature = "os")]
             ByteStreamSource::Child(child) => child.wait(),
         }
     }
@@ -575,6 +598,7 @@ impl ByteStream {
             ByteStreamSource::File(file) => {
                 copy_with_signals(file, dest, span, signals)?;
             }
+            #[cfg(feature = "os")]
             ByteStreamSource::Child(mut child) => {
                 // All `OutDest`s except `OutDest::PipeSeparate` will cause `stderr` to be `None`.
                 // Only `save`, `tee`, and `complete` set the stderr `OutDest` to `OutDest::PipeSeparate`,

crates/nu-std/Cargo.toml

@@ -9,8 +9,8 @@ version = "0.100.1"
 
 [dependencies]
 nu-parser = { version = "0.100.1", path = "../nu-parser" }
-nu-protocol = { version = "0.100.1", path = "../nu-protocol" }
+nu-protocol = { version = "0.100.1", path = "../nu-protocol", default-features = false }
-nu-engine = { version = "0.100.1", path = "../nu-engine" }
+nu-engine = { version = "0.100.1", path = "../nu-engine", default-features = false }
 miette = { workspace = true, features = ["fancy-no-backtrace"] }
 
 log = "0.4"

crates/nu-table/Cargo.toml

@@ -14,9 +14,9 @@ bench = false
 workspace = true
 
 [dependencies]
-nu-protocol = { path = "../nu-protocol", version = "0.100.1" }
+nu-protocol = { path = "../nu-protocol", version = "0.100.1", default-features = false }
-nu-utils = { path = "../nu-utils", version = "0.100.1" }
+nu-utils = { path = "../nu-utils", version = "0.100.1", default-features = false }
-nu-engine = { path = "../nu-engine", version = "0.100.1" }
+nu-engine = { path = "../nu-engine", version = "0.100.1", default-features = false }
 nu-color-config = { path = "../nu-color-config", version = "0.100.1" }
 nu-ansi-term = { workspace = true }
 fancy-regex = { workspace = true }

crates/nu-term-grid/Cargo.toml

@@ -14,6 +14,6 @@ bench = false
 workspace = true
 
 [dependencies]
-nu-utils = { path = "../nu-utils", version = "0.100.1" }
+nu-utils = { path = "../nu-utils", version = "0.100.1", default-features = false }
 
 unicode-width = { workspace = true }

crates/nu-utils/Cargo.toml

@@ -17,6 +17,7 @@ bench = false
 bench = false
 
 [dependencies]
+crossterm = { workspace = true, optional = true }
 fancy-regex = { workspace = true }
 lscolors = { workspace = true, default-features = false, features = ["nu-ansi-term"] }
 log = { workspace = true }
@@ -26,6 +27,10 @@ serde = { workspace = true }
 sys-locale = "0.3"
 unicase = "2.8.0"
 
+[features]
+default = ["os"]
+os = ["crossterm"]
+
 [target.'cfg(windows)'.dependencies]
 crossterm_winapi = "0.9"
 

crates/nu-utils/src/filesystem.rs

@@ -1,3 +1,4 @@
+#[cfg(any(windows, unix))]
 use std::path::Path;
 #[cfg(unix)]
 use {

crates/nu-utils/src/lib.rs

@@ -12,7 +12,7 @@ pub use locale::get_system_locale;
 pub use utils::{
     enable_vt_processing, get_default_config, get_default_env, get_ls_colors, get_sample_config,
     get_sample_env, get_scaffold_config, get_scaffold_env, stderr_write_all_and_flush,
-    stdout_write_all_and_flush,
+    stdout_write_all_and_flush, terminal_size,
 };
 
 pub use casing::IgnoreCaseExt;

crates/nu-utils/src/utils.rs

@@ -1,7 +1,7 @@
 #[cfg(windows)]
 use crossterm_winapi::{ConsoleMode, Handle};
 use lscolors::LsColors;
-use std::io::{Result, Write};
+use std::io::{self, Result, Write};
 
 pub fn enable_vt_processing() -> Result<()> {
     #[cfg(windows)]
@@ -474,3 +474,17 @@ macro_rules! perf {
         }
     };
 }
+
+/// Returns the terminal size (columns, rows).
+///
+/// This utility variant allows getting a fallback value when compiling for wasm32 without having
+/// to rearrange other bits of the codebase.
+///
+/// See [`crossterm::terminal::size`].
+pub fn terminal_size() -> io::Result<(u16, u16)> {
+    #[cfg(feature = "os")]
+    return crossterm::terminal::size();
+
+    #[cfg(not(feature = "os"))]
+    return Err(io::Error::from(io::ErrorKind::Unsupported));
+}

crates/nu_plugin_custom_values/Cargo.toml

@@ -10,7 +10,7 @@ name = "nu_plugin_custom_values"
 bench = false
 
 [dependencies]
-nu-plugin = { path = "../nu-plugin", version = "0.100.1" }
+nu-plugin = { path = "../nu-plugin", version = "0.100.1", features = [] }
 nu-protocol = { path = "../nu-protocol", version = "0.100.1", features = ["plugin"] }
 serde = { workspace = true }
 typetag = "0.2"

crates/nuon/Cargo.toml

@@ -11,9 +11,9 @@ version = "0.100.1"
 
 [dependencies]
 nu-parser = { path = "../nu-parser", version = "0.100.1" }
-nu-protocol = { path = "../nu-protocol", version = "0.100.1" }
+nu-protocol = { path = "../nu-protocol", version = "0.100.1", default-features = false }
-nu-engine = { path = "../nu-engine", version = "0.100.1" }
+nu-engine = { path = "../nu-engine", version = "0.100.1", default-features = false }
-nu-utils = { path = "../nu-utils", version = "0.100.1" }
+nu-utils = { path = "../nu-utils", version = "0.100.1", default-features = false }
 
 [dev-dependencies]
 chrono = { workspace = true }

toolkit.nu

@@ -363,6 +363,40 @@ export def build [
     }
 }
 
+# build crates for wasm
+export def "build wasm" [] {
+    ^rustup target add wasm32-unknown-unknown
+
+    # these crates should compile for wasm
+    let compatible_crates = [
+        "nu-cmd-base",
+        "nu-cmd-extra",
+        "nu-cmd-lang",
+        "nu-color-config",
+        "nu-command",
+        "nu-derive-value",
+        "nu-engine",
+        "nu-glob",
+        "nu-json",
+        "nu-parser",
+        "nu-path",
+        "nu-pretty-hex",
+        "nu-protocol",
+        "nu-std",
+        "nu-system",
+        "nu-table",
+        "nu-term-grid",
+        "nu-utils",
+        "nuon"
+    ]
+
+    for crate in $compatible_crates {
+            print $'(char nl)Building ($crate) for wasm'
+            print '----------------------------'
+        ^cargo build -p $crate --target wasm32-unknown-unknown --no-default-features
+    }
+}
+
 def "nu-complete list features" [] {
     open Cargo.toml | get features | transpose feature dependencies | get feature
 }