Force Matrix m.notices to be unchanged events

src/discord/utils.js

@@ -153,6 +153,26 @@ function howOldUnbridgedMessage(oldTimestamp, newTimestamp) {
 	return dateDisplay
 }
 
+/**
+ * Modifies the input, removing items that don't pass the filter. Returns the items that didn't pass.
+ * @param {T[]} xs
+ * @param {(x: T, i?: number) => any} fn
+ * @template T
+ * @returns T[]
+ */
+function filterTo(xs, fn) {
+	/** @type {T[]} */
+	const filtered = []
+	for (let i = xs.length-1; i >= 0; i--) {
+		const x = xs[i]
+		if (!fn(x, i)) {
+			filtered.unshift(x)
+			xs.splice(i, 1)
+		}
+	}
+	return filtered
+}
+
 module.exports.getPermissions = getPermissions
 module.exports.hasPermission = hasPermission
 module.exports.hasSomePermissions = hasSomePermissions
@@ -163,3 +183,4 @@ module.exports.snowflakeToTimestampExact = snowflakeToTimestampExact
 module.exports.timestampToSnowflakeInexact = timestampToSnowflakeInexact
 module.exports.getPublicUrlForCdn = getPublicUrlForCdn
 module.exports.howOldUnbridgedMessage = howOldUnbridgedMessage
+module.exports.filterTo = filterTo

src/discord/utils.test.js

@@ -192,3 +192,10 @@ test("how old: hours", t => {
 test("how old: days", t => {
 	t.equal(utils.howOldUnbridgedMessage("2024-01-01", "2025-01-01"), "a 366-day-old unbridged message")
 })
+
+test("filterTo: works", t => {
+	const fruit = ["apple", "banana", "apricot"]
+	const rest = utils.filterTo(fruit, f => f[0] === "b")
+	t.deepEqual(fruit, ["banana"])
+	t.deepEqual(rest, ["apple", "apricot"])
+})