Name: js-handler/node_modules/restify/node_modules/once/once.js 
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module.exports = once
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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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})
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function once (fn) {
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  var called = false
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  return function () {
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    if (called) return
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    called = true
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    return fn.apply(this, arguments)
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  }
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}