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