dioxus/README.md
Jonathan Kelley 508c560320 Feat: massive changes to definition of components
This change switches back to the original `ctx<props>` syntax for
commponents. This lets lifetime elision to remove the need to match
exactly which lifetime (props or ctx) gets  carried to the output. As
such, `Props` is currently required to be static. It *is* possible to
loosen this restriction, and will be done in the future, though only
through adding metadata about the props through the Props derive
macro. Implementing the IS_STATIC trait is unsafe, so the derive macro
will do it through some heuristics.

For now, this unlocks sharing vnodes from parents to children, enabling
pass-thru components, fragments, portals, etc.
2021-06-01 18:33:15 -04:00

7.6 KiB

🌗🚀 Dioxus

Frontend that scales.

Dioxus is a portable, performant, and ergonomic framework for building cross-platform user experiences in Rust.

//! A complete dioxus web app
use dioxus_web::*;

struct Props { initial_text: &'static str }

fn Example(ctx: Context<Props>) -> VNode {
    let selection = use_state(ctx, move || ctx.initial_text);

    ctx.render(rsx! {
        div {
            h1 { "Hello, {selection}" }
            button { "?", onclick: move |_| selection.set("world!")}
            button { "?", onclick: move |_| selection.set("Dioxus 🎉")}
        }
    })
};

fn main() {
    dioxus_web::start_with_props(Example, Props { initial_text: "..?" }).block_on();
}

Dioxus can be used to deliver webapps, desktop apps, static pages, liveview apps, Android apps, iOS Apps, and more. At its core, Dioxus is entirely renderer agnostic and has great documentation for creating new renderers for any platform.

If you know React, then you already know Dioxus.

Things you'll love ❤️:

  • Ergonomic design
  • Minimal boilerplate
  • Familiar design and semantics
  • Simple build, test, and deploy
  • Support for html! and rsx! templating
  • SSR, WASM, desktop, and mobile support
  • Powerful and simple integrated state management
  • Rust! (enums, static types, modules, efficiency)

Get Started with...

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Explore

Blog Posts

  • Why we need a stronger typed web
  • Isomorphic webapps in 10 minutes
  • Rust is high level too
  • Eliminating crashes with Rust webapps
  • Tailwind for Dioxus
  • The monoglot startup

FAQ

Why?


TypeScript is a great addition to JavaScript, but comes with a lot of tweaking flags, a slight performance hit, and an uneven ecosystem where some of the most important packages are not properly typed. TypeScript provides a lot of great benefits to JS projects, but comes with its own "tax" that can slow down dev teams. Rust can be seen as a step up from TypeScript, supporting:

  • static types for all libraries
  • advanced pattern matching
  • immutability by default
  • clean, composable iterators
  • a good module system
  • integrated documentation
  • inline built-in unit/integration testing
  • best-in-class error handling
  • simple and fast build system
  • include_str! for integrating html/css/svg templates directly
  • various macros (html!, rsx!) for fast template iteration

And much more. Dioxus makes Rust apps just as fast to write as React apps, but affords more robustness, giving your frontend team greater confidence in making big changes in shorter time. Dioxus also works on the server, on the web, on mobile, on desktop - and it runs completely natively so performance is never an issue.

Immutability by default?


Rust, like JS and TS, supports both mutable and immutable data. With JS, const would be used to signify immutable data, while in rust, the absence of mut signifies immutable data.

Mutability:

let mut val = 10; // rust
let val = 10;     // js

Immutability

let val = 10;    // rust
const val = 10;  // js

However, const in JS does not prohibit you from modify the value itself only disallowing assignment. In Rust, immutable is immutable. You never have to work about accidentally mutating data; mutating immutable data in Rust requires deliberate advanced datastructures that you won't find in your typical frontend code.

How do strings work?


In rust, we have &str, &'static str String, and Rc<str>. It's a lot, yes, and it might be confusing at first. But it's actually not too bad.

In Rust, UTF-8 is supported natively, allowing for emoji and extended character sets (like Chinese and Arabic!) instead of the typical ASCII. The primitive str can be seen as a couple of UTF-8 code points squished together with a dynamic size. Because this size is variable (not known at compile time for any single character), we reference an array of UTF-8 code points as &str. Essentially, we're referencing (the & symbol) some dynamic str (a collection of UTF-8 points).

For text encoded directly in your code, this collection of UTF-8 code points is given the 'static reference lifetime - essentially meaning the text can be safely referenced for the entire runtime of your program. Contrast this with JS, where a string will only exist for as long as code references it before it gets cleaned up by the garbage collector.

For text that needs to have characters added, removed, sorted, uppercased, formatted, accessed for mutation, etc, Rust has the String type, which is essentially just a dynamically sized str. In JS, if you add a character to your string, you actually create an entirely new string (completely cloning the old one first). In Rust, you can safely added characters to strings without having to clone first, making string manipulation in Rust very efficient.

Finally, we have Rc<str>. This is essentially Rust's version of JavaScript's string. In JS, whenever you pass a string around (and don't mutate it), you don't actually clone it, but rather just increment a counter that says "this code is using this string." This counter prevents the garbage collector from deleting the string before your code is done using it. Only when all parts of your code are done with the string, will the string be deleted. Rc<str> works exactly the same way in Rust, but requires a deliberate .clone() to get the same behavior. In most instances, Dioxus will automatically do this for you, saving the trouble of having to clone when you pass an Rc<str> into child components. Rc<str> is typically better than String for Rust - it allows cheap sharing of strings, and through make_mut you can always produce your own mutable copy for modifying. You might not see Rc<str> in other Rust libraries as much, but you will see it in Dioxus due to Dioxus' aggressive memoization and focus on efficiency and performance.

If you run into issues with &str, String, Rc<str>, just try cloning and to_string first. For the vast majority of apps, the slight performance hit will be unnoticeable. Once you get better with Strings, it's very easy to go back and remove all the clones for more efficient alternatives, but you will likely never need to.