1 files changed, 84 insertions, 0 deletions
diff --git a/src/renderer/util.ts b/src/renderer/util.ts
new file mode 100644
index 0000000..cea404b
--- /dev/null
+++ b/src/renderer/util.ts
@@ -0,0 +1,84 @@
+export function recordToMap<T>(r: Record<string, T>): Map<string, T> {
+	const ret = new Map();
+
+	for (const k of Object.keys(r))
+		ret.set(k, r[k]);
+
+	return ret;
+}
+
+export function mapValues<K, V1, V2>(f: (v: V1) => V2, map: Map<K, V1>): Map<K, V2> {
+	const ret: Map<K, V2> = new Map();
+
+	for (const [k, v] of map)
+		ret.set(k, f(v));
+
+	return ret;
+}
+
+export async function mapValuesAsync<K, V1, V2>(f: (v: V1) => Promise<V2>, map: Map<K, V1>): Promise<Map<K, V2>> {
+	const ret: Map<K, V2> = new Map();
+
+	for (const [k, v] of mapValues(f, map))
+		ret.set(k, await v);
+
+	return ret;
+}
+
+export function nextPowerOf2(n: number): number {
+	let i = 1;
+
+	while (i < n)
+		i *= 2;
+
+	return i;
+}
+
+export class Listenable<T extends any[]> {
+	private readonly listeners: Array<(...args: T) => void> = [];
+
+	public addListener(listener: (...args: T) => void): void {
+		this.listeners.push(listener);
+	}
+
+	protected runListeners(...args: T): void {
+		this.listeners.forEach((l) => l(...args));
+	}
+}
+
+export function get(url: string): Promise<XMLHttpRequest> {
+	return new Promise((resolve, reject) => {
+		const xhr = new XMLHttpRequest();
+
+		const handleError = () => {
+			if (xhr.readyState !== xhr.DONE) {
+				reject(new Error('HTTP request ended in state ' + xhr.readyState));
+				return;
+			}
+
+			reject(new Error('HTTP request returned status ' + xhr.status));
+		};
+
+		xhr.addEventListener('error', handleError);
+
+		xhr.addEventListener('load', () => {
+			if (xhr.readyState !== xhr.DONE || xhr.status !== 200) {
+				handleError();
+				return;
+			}
+
+			resolve(xhr);
+		});
+
+		xhr.open('GET', url, true);
+		xhr.send();
+	});
+}
+
+export async function getJSON(url: string): Promise<any> {
+	return JSON.parse((await get(url)).responseText);
+}
+
+export function nextAnimationFrame(): Promise<DOMHighResTimeStamp> {
+	return new Promise((resolve) => window.requestAnimationFrame(resolve));
+}