30 lines
1014 B
JavaScript
30 lines
1014 B
JavaScript
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'use strict';
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var $TypeError = require('es-errors/type');
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var DefinePropertyOrThrow = require('./DefinePropertyOrThrow');
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var HasOwnProperty = require('./HasOwnProperty');
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var IsExtensible = require('./IsExtensible');
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var isInteger = require('../helpers/isInteger');
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// https://262.ecma-international.org/12.0/#sec-setfunctionlength
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module.exports = function SetFunctionLength(F, length) {
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if (typeof F !== 'function' || !IsExtensible(F) || HasOwnProperty(F, 'length')) {
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throw new $TypeError('Assertion failed: `F` must be an extensible function and lack an own `length` property');
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}
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if (typeof length !== 'number') {
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throw new $TypeError('Assertion failed: `length` must be a Number');
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}
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if (length !== Infinity && (!isInteger(length) || length < 0)) {
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throw new $TypeError('Assertion failed: `length` must be ∞, or an integer >= 0');
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}
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return DefinePropertyOrThrow(F, 'length', {
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'[[Configurable]]': true,
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'[[Enumerable]]': false,
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'[[Value]]': length,
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'[[Writable]]': false
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});
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};
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