Bring all the lib/utils from the frontend to the backend.

The idea being that eventually we will symlink the lib/utils
directory so that the same routines are available on both the
frontend and the backend.

lib/www/server/lib/utils/FormatTimestamp.js

@@ -0,0 +1,13 @@
+
+
+function FormatTimestamp (str) {
+  const d = new Date(str);
+  if (isNaN(d)) {
+    return str;
+  } else {
+    // Get rid of milliseconds
+    return d.toISOString().substring(0,19)+"Z";
+  }
+}
+
+module.exports = FormatTimestamp;

lib/www/server/lib/utils/deep.js

@@ -0,0 +1,168 @@
+
+/** Compare two possibly complex values for
+ * loose equality, going as deep as required in the
+ * case of complex objects.
+ */
+function deepCompare (a, b) {
+  if (typeof a == "object" && typeof b == "object") {
+    return !Object.entries(a).some( ([k, v]) => !deepCompare(v, b[k])) &&
+      !Object.entries(b).some( ([k, v]) => !deepCompare(v, a[k]));
+  } else {
+    return a == b;
+  }
+}
+
+
+/** Compare two possibly complex values for
+ * strict equality.
+ */
+function deepEqual (a, b) {
+  if (typeof a === "object" && typeof b === "object") {
+    return !Object.entries(a).some( ([k, v]) => !deepEqual(v, b[k])) &&
+      !Object.entries(b).some( ([k, v]) => !deepEqual(v, a[k]));
+  } else {
+    return a === b;
+  }
+}
+
+/** Traverses an object and sets a nested value.
+ *
+ * Example:
+ *
+ * const obj = {a: {b: {c: "X"} } }
+ * deepSet(obj, ["a", "b", "c"], "d")
+ * → {a: {b: {c: "d"} } }
+ *
+ * This would be the equivalent of:
+ *
+ * obj?.a?.b?.c = "d";
+ *
+ * Except that the above is not a legal expression.
+ *
+ * If a non-leaf property does not exist, this function
+ * creates it as an empty object ({}) and keeps traversing.
+ *
+ * The last member of `path` may be `null`, in which case,
+ * if the object pointed to by the next to last member is
+ * an array, an insert operation will take place.
+ *
+ */
+function deepSet (obj, path, value) {
+  const key = path.shift();
+  if (!path.length) {
+    if (key === null && Array.isArray(obj)) {
+      obj.push(value);
+    } else {
+      obj[key] = value;
+    }
+  } else {
+    if (!Object.hasOwn(obj, key)) {
+      obj[key] = {};
+    }
+    deepSet(obj[key], path, value);
+  }
+}
+
+/** Returns a nested property.
+ *
+ * Example:
+ *
+ * const obj = {a: {b: {c: "d"} } }
+ * deepSet(obj, ["a", "b", "c"])
+ * → "d"
+ *
+ * If `path` is known in advance, this is effectively
+ * the same as:
+ *
+ * obj?.a?.b?.c
+ *
+ * This might be useful when `path` is dynamic.
+ */
+function deepValue (obj, path) {
+  if (obj !== undefined) {
+    const key = path.shift();
+    if (!path.length) {
+      if (key === undefined) {
+        return obj;
+      } else {
+        return obj[key];
+      }
+    } else {
+      return deepValue(obj[key], path);
+    }
+  }
+}
+
+// Copied from:
+// https://gomakethings.com/how-to-deep-merge-arrays-and-objects-with-javascript/
+
+/*!
+ * Deep merge two or more objects or arrays.
+ * (c) 2023 Chris Ferdinandi, MIT License, https://gomakethings.com
+ * @param   {*} ...objs  The arrays or objects to merge
+ * @returns {*}          The merged arrays or objects
+ */
+function deepMerge (...objs) {
+
+	/**
+	 * Get the object type
+	 * @param  {*}       obj The object
+	 * @return {String}      The object type
+	 */
+	function getType (obj) {
+		return Object.prototype.toString.call(obj).slice(8, -1).toLowerCase();
+	}
+
+	/**
+	 * Deep merge two objects
+	 * @return {Object}
+	 */
+	function mergeObj (clone, obj) {
+		for (let [key, value] of Object.entries(obj)) {
+			let type = getType(value);
+			if (clone[key] !== undefined && getType(clone[key]) === type && ['array', 'object'].includes(type)) {
+				clone[key] = deepMerge(clone[key], value);
+			} else {
+				clone[key] = structuredClone(value);
+			}
+		}
+	}
+
+	// Create a clone of the first item in the objs array
+	let clone = structuredClone(objs.shift());
+
+	// Loop through each item
+	for (let obj of objs) {
+
+		// Get the object type
+		let type = getType(obj);
+
+		// If the current item isn't the same type as the clone, replace it
+		if (getType(clone) !== type) {
+			clone = structuredClone(obj);
+			continue;
+		}
+
+		// Otherwise, merge
+		if (type === 'array') {
+			// Replace old array with new
+			clone = [...structuredClone(obj)];
+		} else if (type === 'object') {
+			mergeObj(clone, obj);
+		} else {
+			clone = obj;
+		}
+
+	}
+
+	return clone;
+
+}
+
+module.exports = {
+	deepCompare,
+	deepEqual,
+	deepSet,
+	deepValue,
+	deepMerge
+};

lib/www/server/lib/utils/hsl.js

@@ -0,0 +1,47 @@
+/** Return an HSL colour as a function of an input value
+  * `str`.
+  *
+  * Consider using as getHSL.bind(this) in Vue components
+  * in order to get access to the Vuetify theme configuration.
+  */
+function getHSL (str, saturation = 1, lightness = 0.25, offset = 0) {
+
+  function getHash (v) {
+    if (typeof (v??false)[Symbol.iterator] != "function") {
+      // Not an iterable, make it one
+      v = String(v);
+    }
+
+    return Math.abs([...v, ..." "].reduce( (acc, cur) => String(cur).charCodeAt(0) + ((acc << 5) - acc), 0 ));
+  }
+
+  const h = (getHash(str) + offset) % 360;
+  const s = saturation * 100;
+  const l = this?.$vuetify?.theme?.isDark
+    ? (1-lightness) * 100
+    : lightness * 100;
+
+  return {h, s, l};
+
+}
+
+/** Return a CSS hsl() or hsla() colour
+ * representation as a function of an input value.
+ *
+ * Consider using as getHSLColourFor.bind(this) – See
+ * note for getHSL() above.
+ */
+function getHSLColourFor (str, opacity = 1, saturation, lightness, offset) {
+  const _getHSL = getHSL.bind(this);
+  const {h, s, l} = _getHSL(str, saturation, lightness, offset);
+  if (opacity == 1) {
+    return `hsl(${h},${s}%,${l}%)`;
+  } else {
+    return `hsla(${h},${s}%,${l}%, ${opacity})`;
+  }
+}
+
+module.exports = {
+  getHSL,
+  getHSLColourFor
+}

lib/www/server/lib/utils/index.js

@@ -1,13 +1,24 @@
 
 module.exports = {
-	geometryAsString: require('./geometryAsString'),
+	...require('./deep'),
 	dms: require('./dms'),
-	replaceMarkers: require('./replaceMarkers'),
+	...require('./flatEntries'),
 	flattenQCDefinitions: require('./flattenQCDefinitions'),
-	deepMerge: require('./deepMerge'),
+	FormatTimestamp: require('./FormatTimestamp'),
+	geometryAsString: require('./geometryAsString'),
+	...require('./hsl'),
+	...require('./logicalPath'), // FIXME Breaking change (used to be logicalPath.…)
+	logicalPath: require('./logicalPath'), // NOTE For compatibility, see above
+	...require('./markdown'),
+	preferencesλ: require('./preferencesλ'),
+	...require('./ranges'), // FIXME Breaking change (used to be ranges.…)
+	ranges: require('./ranges'), // NOTE For compatibility, see above.
 	removeNulls: require('./removeNulls'),
-	logicalPath: require('./logicalPath'),
-	ranges: require('./ranges'),
+	replaceMarkers: require('./replaceMarkers'),
+	setContentDisposition: require('./setContentDisposition'),
+	throttle: require('./throttle'),
+	truncateText: require('./truncateText'),
 	unique: require('./unique'),
-	setContentDisposition: require('./setContentDisposition')
+	unpack: require('./unpack'),
+	withParentProps: require('./withParentProps')
 };

lib/www/server/lib/utils/markdown.js

@@ -0,0 +1,11 @@
+const { marked, parseInline } = require('marked');
+
+function markdown (str) {
+  return marked(String(str));
+}
+
+function markdownInline (str) {
+  return parseInline(String(str));
+}
+
+module.exports = { markdown, markdownInline };

lib/www/server/lib/utils/preferencesλ.js

@@ -0,0 +1,44 @@
+
+
+/** Extract preferences by prefix.
+ *
+ * This function returns a lambda which, given
+ * a key or a prefix, extracts the relevant
+ * preferences from the designated preferences
+ * store.
+ *
+ * For instance, assume preferences = {
+ *   "a.b.c.d": 1,
+ *   "a.b.e.f": 2,
+ *   "g.h": 3
+ * }
+ *
+ * And λ = preferencesλ(preferences). Then:
+ *
+ * λ("a.b") → { "a.b.c.d": 1, "a.b.e.f": 2 }
+ * λ("a.b.e.f") → { "a.b.e.f": 2 }
+ * λ("g.x", {"g.x.": 99}) → { "g.x.": 99 }
+ * λ("a.c", {"g.x.": 99}) → { "g.x.": 99 }
+ *
+ * Note from the last  two examples that a default value
+ * may be provided and will be returned if a key does
+ * not exist or is not searched for.
+ */
+function preferencesλ (preferences) {
+
+  return function (key, defaults={}) {
+    const keys = Object.keys(preferences).filter(str => str.startsWith(key+".") || str == key);
+
+    const settings = {...defaults};
+    for (const str of keys) {
+      const k = str == key ? str : str.substring(key.length+1);
+      const v = preferences[str];
+      settings[k] = v;
+    }
+
+    return settings;
+  }
+
+}
+
+module.exports = preferencesλ;

lib/www/server/lib/utils/throttle.js

@@ -0,0 +1,33 @@
+/**
+ * Throttle a function call.
+ *
+ * It delays `callback` by `delay` ms and ignores any
+ * repeated calls from `caller` within at most `maxWait`
+ * milliseconds.
+ *
+ * Used to react to server events in cases where we get
+ * a separate notification for each row of a bulk update.
+ */
+function throttle (callback, caller, delay = 100, maxWait = 500) {
+
+  const schedule = async () => {
+    caller.triggeredAt = Date.now();
+    caller.timer = setTimeout(async () => {
+      await callback();
+      caller.timer = null;
+    }, delay);
+  }
+
+  if (!caller.timer) {
+    schedule();
+  } else {
+    const elapsed = Date.now() - caller.triggeredAt;
+    if (elapsed > maxWait) {
+      cancelTimeout(caller.timer);
+      schedule();
+    }
+  }
+
+}
+
+module.exports = throttle;

lib/www/server/lib/utils/truncateText.js

@@ -0,0 +1,10 @@
+
+function truncateText (text, length=20) {
+  if (text?.length <= length) {
+    return text;
+  } else {
+    return text.slice(0, length/2)+"…"+text.slice(-(length/2));
+  }
+}
+
+module.exports = truncateText;

lib/www/server/lib/utils/unpack.js

@@ -0,0 +1,35 @@
+/** Unpacks attributes from array items.
+ *
+ * At it simplest, given an array of objects,
+ * the call unpack(rows, "x") returns an array
+ * of the "x" attribute of every item in rows.
+ *
+ * `key` may also be:
+ *
+ * - a function with the signature
+ *   (Object) => any
+ *   the result of applying the function to
+ *   the object will be used as the unpacked
+ *   value.
+ *
+ * - an array of strings, functions or other
+ *   arrays. In this case, it does a recursive
+ *   fold operation. NOTE: it mutates `key`.
+ *
+ */
+function unpack(rows, key) {
+  if (typeof key === "function") {
+    return rows && rows.map( row => key(row) );
+  } else if (Array.isArray(key)) {
+    const car = key.shift();
+    if (key.length) {
+      return unpack(unpack(rows, car), key);
+    } else {
+      return unpack(rows, car);
+    }
+  } else {
+    return rows && rows.map( row => row?.[key] );
+  }
+};
+
+module.exports = unpack;

lib/www/server/lib/utils/withParentProps.js

@@ -0,0 +1,28 @@
+
+function withParentProps(item, parent, childrenKey, prop, currentValue) {
+	if (!Array.isArray(parent)) {
+		return;
+	}
+
+	let currentPropValue = currentValue || parent[prop];
+
+	for (const entry of parent) {
+		if (entry[prop]) {
+			currentPropValue = entry[prop];
+		}
+
+		if (entry === item) {
+			return [item, currentPropValue];
+		}
+
+		if (entry[childrenKey]) {
+			const res = withParentProps(item, entry[childrenKey], childrenKey, prop, currentPropValue);
+            if (res[1]) {
+              return res;
+            }
+		}
+	}
+	return [];
+}
+
+module.exports = withParentProps;