42 lines
1.1 KiB
JavaScript
42 lines
1.1 KiB
JavaScript
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'use strict';
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var GetIntrinsic = require('get-intrinsic');
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var define = require('define-data-property');
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var hasDescriptors = require('has-property-descriptors')();
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var gOPD = require('gopd');
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var $TypeError = GetIntrinsic('%TypeError%');
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var $floor = GetIntrinsic('%Math.floor%');
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module.exports = function setFunctionLength(fn, length) {
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if (typeof fn !== 'function') {
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throw new $TypeError('`fn` is not a function');
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}
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if (typeof length !== 'number' || length < 0 || length > 0xFFFFFFFF || $floor(length) !== length) {
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throw new $TypeError('`length` must be a positive 32-bit integer');
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}
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var loose = arguments.length > 2 && !!arguments[2];
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var functionLengthIsConfigurable = true;
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var functionLengthIsWritable = true;
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if ('length' in fn && gOPD) {
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var desc = gOPD(fn, 'length');
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if (desc && !desc.configurable) {
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functionLengthIsConfigurable = false;
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}
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if (desc && !desc.writable) {
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functionLengthIsWritable = false;
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}
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}
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if (functionLengthIsConfigurable || functionLengthIsWritable || !loose) {
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if (hasDescriptors) {
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define(fn, 'length', length, true, true);
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} else {
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define(fn, 'length', length);
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}
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}
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return fn;
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};
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