40 lines
709 B
JavaScript
40 lines
709 B
JavaScript
'use strict';
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const mimicFn = require('mimic-fn');
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module.exports = (fn, opts) => {
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// TODO: Remove this in v3
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if (opts === true) {
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throw new TypeError('The second argument is now an options object');
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}
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if (typeof fn !== 'function') {
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throw new TypeError('Expected a function');
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}
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opts = opts || {};
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let ret;
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let called = false;
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const fnName = fn.displayName || fn.name || '<anonymous>';
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const onetime = function () {
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if (called) {
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if (opts.throw === true) {
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throw new Error(`Function \`${fnName}\` can only be called once`);
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}
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return ret;
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}
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called = true;
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ret = fn.apply(this, arguments);
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fn = null;
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return ret;
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};
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mimicFn(onetime, fn);
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return onetime;
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};
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