77 lines
1.7 KiB
JavaScript
77 lines
1.7 KiB
JavaScript
var assign = require('./assign')
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/**
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* 函数去抖；当被调用 n 毫秒后才会执行，如果在这时间内又被调用则将重新计算执行时间
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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 debounce (callback, wait, options) {
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var args = null
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var context = null
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var opts = typeof options === 'boolean' ? { leading: options, trailing: !options } : assign({ leading: false, trailing: true }, options)
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var runFlag = false
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var timeout = null
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var optLeading = opts.leading
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var optTrailing = opts.trailing
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var gcFn = function () {
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args = null
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context = null
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}
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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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gcFn()
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}
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var endFn = function () {
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if (optLeading === true) {
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timeout = null
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}
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if (runFlag) {
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gcFn()
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return
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}
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if (optTrailing === true) {
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runFn()
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return
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}
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gcFn()
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}
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var cancelFn = function () {
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var rest = timeout !== null
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if (rest) {
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clearTimeout(timeout)
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}
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gcFn()
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timeout = null
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runFlag = false
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return rest
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}
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var debounced = function () {
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runFlag = false
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args = arguments
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context = this
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if (timeout === null) {
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if (optLeading === true) {
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runFn()
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}
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} else {
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clearTimeout(timeout)
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}
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timeout = setTimeout(endFn, wait)
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}
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debounced.cancel = cancelFn
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return debounced
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}
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module.exports = debounce
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