38 lines
924 B
JavaScript
38 lines
924 B
JavaScript
'use strict';
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/**
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* Wrap callbacks to prevent double execution.
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*
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* @param {Function} fn Function that should only be called once.
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* @returns {Function} A wrapped callback which prevents execution.
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* @api public
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*/
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module.exports = function one(fn) {
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var called = 0
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, value;
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/**
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* The function that prevents double execution.
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*
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* @api private
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*/
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function onetime() {
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if (called) return value;
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called = 1;
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value = fn.apply(this, arguments);
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fn = null;
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return value;
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}
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//
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// To make debugging more easy we want to use the name of the supplied
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// function. So when you look at the functions that are assigned to event
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// listeners you don't see a load of `onetime` functions but actually the
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// names of the functions that this module will call.
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//
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onetime.displayName = fn.displayName || fn.name || onetime.displayName || onetime.name;
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return onetime;
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};
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