// cancelAnimationFrame
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export const cancelAnimationFrame = window.cancelAnimationFrame;
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// 使用 requestAnimationFrame 模拟 setTimeout 和 setInterval
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export function rafTimeout(fn: Function, delay = 0, interval = false): object {
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const requestAnimationFrame =
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typeof window !== 'undefined' ? window.requestAnimationFrame : () => {};
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let start: any = null;
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function timeElapse(timestamp: number) {
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/*
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timestamp参数：与performance.now()的返回值相同，它表示requestAnimationFrame() 开始去执行回调函数的时刻
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*/
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if (!start) {
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start = timestamp;
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}
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const elapsed = timestamp - start;
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if (elapsed >= delay) {
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fn(); // 执行目标函数func
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if (interval) {
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// 使用间歇调用
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start = null;
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raf.id = requestAnimationFrame(timeElapse);
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}
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} else {
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raf.id = requestAnimationFrame(timeElapse);
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}
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}
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const raf = {
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// 引用类型保存，方便获取 requestAnimationFrame()方法返回的 ID.
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id: requestAnimationFrame(timeElapse),
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};
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return raf;
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}
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// 用于取消 rafTimeout 函数
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export function cancelRaf(raf: { id: number }): void {
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const cancelAnimationFrame =
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typeof window !== 'undefined' ? window.cancelAnimationFrame : () => {};
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if (raf && raf.id) {
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cancelAnimationFrame(raf.id);
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}
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}
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