32 lines
608 B
JavaScript
32 lines
608 B
JavaScript
'use strict';
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module.exports = function (fn, errMsg) {
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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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var ret;
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var called = false;
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var fnName = fn.displayName || fn.name || (/function ([^\(]+)/.exec(fn.toString()) || [])[1];
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var onetime = function () {
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if (called) {
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if (errMsg === true) {
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fnName = fnName ? fnName + '()' : 'Function';
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throw new Error(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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onetime.displayName = fnName;
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return onetime;
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};
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