43 lines
935 B
JavaScript
43 lines
935 B
JavaScript
var wrappy = require('wrappy')
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module.exports = wrappy(once)
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module.exports.strict = wrappy(onceStrict)
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once.proto = once(function () {
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Object.defineProperty(Function.prototype, 'once', {
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value: function () {
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return once(this)
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},
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configurable: true
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})
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Object.defineProperty(Function.prototype, 'onceStrict', {
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value: function () {
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return onceStrict(this)
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},
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configurable: true
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})
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})
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function once (fn) {
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var f = function () {
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if (f.called) return f.value
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f.called = true
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return f.value = fn.apply(this, arguments)
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}
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f.called = false
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return f
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}
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function onceStrict (fn) {
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var f = function () {
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if (f.called)
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throw new Error(f.onceError)
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f.called = true
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return f.value = fn.apply(this, arguments)
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}
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var name = fn.name || 'Function wrapped with `once`'
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f.onceError = name + " shouldn't be called more than once"
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f.called = false
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return f
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}
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