51 lines
1.3 KiB
Java
51 lines
1.3 KiB
Java
/**
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* 节流函数；当被调用 n 毫秒后才会执行，如果在这时间内又被调用则至少每隔 n 秒毫秒调用一次该函数
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*
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* @param {Function} callback 回调
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* @param {Number} wait 多少秒毫
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* @param {Object} options 参数{leading: 是否在之前执行, trailing: 是否在之后执行}
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* @return {Function}
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*/
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function throttle (callback, wait, options) {
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var args, context
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var opts = options || {}
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var runFlag = false
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var timeout = 0
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var optLeading = 'leading' in opts ? opts.leading : true
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var optTrailing = 'trailing' in opts ? opts.trailing : false
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var runFn = function () {
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runFlag = true
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callback.apply(context, args)
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timeout = setTimeout(endFn, wait)
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}
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var endFn = function () {
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timeout = 0
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if (!runFlag && optTrailing === true) {
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runFn()
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}
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}
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var cancelFn = function () {
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var rest = timeout !== 0
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clearTimeout(timeout)
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runFlag = false
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timeout = 0
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return rest
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}
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var throttled = function () {
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args = arguments
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context = this
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runFlag = false
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if (timeout === 0) {
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if (optLeading === true) {
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runFn()
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} else if (optTrailing === true) {
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timeout = setTimeout(endFn, wait)
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}
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}
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}
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throttled.cancel = cancelFn
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return throttled
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}
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module.exports = throttle
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