Added TypeScript types (#1)

index.d.ts

@@ -0,0 +1,44 @@
+/// <reference lib="dom" />
+
+export interface CancelCallback {
+	(requestId: number): void;
+}
+
+interface IntervalometerReturnValue {
+	start: VoidFunction;
+	stop: VoidFunction;
+}
+
+/**
+ * @param callback A callback that will be called.
+ * @param request A window's requestAnimationFrame or setTimeout.
+ * @param cancel A callback that will cancel the given intervalometer. Typically a window's cancelAnimationFrame or clearTimeout.
+ * @param millis Time in milliseconds.
+ */
+export function intervalometer(
+	callback: VoidFunction,
+	request: typeof requestAnimationFrame | typeof setTimeout,
+	cancel: CancelCallback,
+	millis?: number
+): IntervalometerReturnValue;
+
+/**
+ * A time-based intervalometer.
+ *
+ * @param callback A callback that will be invoked after the given time-frame.
+ * @param timeInMillis Time in milliseconds.
+ */
+export function timerIntervalometer(
+	callback: VoidFunction,
+	timeInMillis: number
+): IntervalometerReturnValue;
+
+/**
+ * A frame-based intervalometer. It uses requestAnimationFrame and calls the provided callback at every frame.
+ * Ideal for animations.
+ *
+ * @param callback A callback that will be called on each animation frame.
+ */
+export function frameIntervalometer(
+	callback: VoidFunction
+): IntervalometerReturnValue;

index.test-d.ts

@@ -0,0 +1,8 @@
+/* eslint-disable import/named */
+
+import {expectType} from 'tsd';
+import {intervalometer, frameIntervalometer, timerIntervalometer, IntervalometerReturnValue} from '.'
+
+expectType<IntervalometerReturnValue>(intervalometer(() => { }, setTimeout, () => { }, 1));
+expectType<IntervalometerReturnValue>(frameIntervalometer(() => { }));
+expectType<IntervalometerReturnValue>(timerIntervalometer(() => { }, 1000));