Add code for DateTime Delta to calculate operation

src/core/operations/DateTimeDelta.mjs

@@ -0,0 +1,109 @@
+/**
+ * @author tomgond [tom.gonda@gmail.com]
+ * @copyright Crown Copyright 2024
+ * @license Apache-2.0
+ */
+
+import Operation from "../Operation.mjs";
+import moment from "moment-timezone";
+import {DATETIME_FORMATS, FORMAT_EXAMPLES} from "../lib/DateTime.mjs";
+
+/**
+  * @param {string} timeString
+  * @returns {string}
+*/
+function parseTimeString(timeString) {
+    // Split the string into its components
+    const parts = timeString.split(":");
+    // Extract the sign, days, hours, minutes, and seconds
+    const sign = parts[0][0] === "-" ? "-" : "+";
+    const days = parseInt(parts[0].split(".")[0].slice(1), 10);
+    const hours = parseInt(parts[0].split(".")[1], 10);
+    const minutes = parseInt(parts[1], 10);
+    const seconds = parseInt(parts[2], 10);
+
+    return {
+        sign,
+        days,
+        hours,
+        minutes,
+        seconds
+    };
+}
+
+/**
+ * DateTime Delta operation
+ */
+class DateTimeDelta extends Operation {
+
+    /**
+     * DateTimeDelta constructor
+     */
+    constructor() {
+        super();
+
+        this.name = "DateTime Delta";
+        this.module = "Default";
+        this.description = "Calculates a new DateTime value given an input DateTime value and a time difference (delta) from the input DateTime value.";
+        this.infoURL = "";
+        this.inputType = "string";
+        this.outputType = "string";
+        this.args = [
+            {
+                "name": "Built in formats",
+                "type": "populateOption",
+                "value": DATETIME_FORMATS,
+                "target": 1
+            },
+            {
+                "name": "Input format string",
+                "type": "binaryString",
+                "value": "DD/MM/YYYY HH:mm:ss"
+            },
+            {
+                "name": "Time Delta",
+                "type": "binaryString",
+                "value": "+0.00:00:00"
+            }
+
+        ];
+    }
+
+
+    /**
+     * @param {string} input
+     * @param {Object[]} args
+     * @returns {string}
+     */
+    run(input, args) {
+        const inputFormat = args[1],
+            inputTimezone = "UTC";
+        const deltaStr = args[2];
+
+        let date = "";
+        try {
+            date = moment.tz(input, inputFormat, inputTimezone);
+            if (!date || date.format() === "Invalid date") throw Error;
+        } catch (err) {
+            return `Invalid format.\n\n${FORMAT_EXAMPLES}`;
+        }
+
+        const deltaDict = parseTimeString(deltaStr);
+        let newDate;
+        if (deltaDict.sign === "-") {
+            newDate = date.add(-deltaDict.days, "days")
+                .add(-deltaDict.hours, "hours")
+                .add(-deltaDict.minutes, "minutes")
+                .add(-deltaDict.seconds, "seconds");
+
+        } else {
+            newDate = date.add(deltaDict.days, "days")
+                .add(deltaDict.hours, "hours")
+                .add(deltaDict.minutes, "minutes")
+                .add(deltaDict.seconds, "seconds");
+        }
+        return newDate.tz(inputTimezone).format(inputFormat.replace(/[<>]/g, ""));
+    }
+}
+
+export default DateTimeDelta;