--- title: recordAnimationFrames tags: browser,utility,intermediate --- Invokes the provided callback on each animation frame. Use recursion. Provided that `running` is `true`, continue invoking `window.requestAnimationFrame()` which invokes the provided callback. Return an object with two methods `start` and `stop` to allow manual control of the recording. Omit the second argument, `autoStart`, to implicitly call `start` when the function is invoked. ```js const recordAnimationFrames = (callback, autoStart = true) => { let running = true, raf; const stop = () => { running = false; cancelAnimationFrame(raf); }; const start = () => { running = true; run(); }; const run = () => { raf = requestAnimationFrame(() => { callback(); if (running) run(); }); }; if (autoStart) start(); return { start, stop }; }; ``` ```js const cb = () => console.log('Animation frame fired'); const recorder = recordAnimationFrames(cb); // logs 'Animation frame fired' on each animation frame recorder.stop(); // stops logging recorder.start(); // starts again const recorder2 = recordAnimationFrames(cb, false); // `start` needs to be explicitly called to begin recording frames ```