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26 lines
558 B
26 lines
558 B
5 months ago
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var slice = require('./slice')
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/**
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* 创建一个只能调用一次的函数,只会返回第一次执行后的结果
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*
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* @param {Function} callback 函数
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* @param {Object} context 上下文
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* @param {*} args 额外的参数
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* @return {Object}
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*/
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function once (callback, context) {
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var done = false
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var rest = null
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var args = slice(arguments, 2)
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return function () {
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if (done) {
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return rest
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}
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rest = callback.apply(context, slice(arguments).concat(args))
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done = true
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return rest
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}
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}
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module.exports = once
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