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- 'use strict';
- var GetIntrinsic = require('get-intrinsic');
- var $RangeError = GetIntrinsic('%RangeError%');
- var $TypeError = GetIntrinsic('%TypeError%');
- var assign = require('object.assign');
- var isPropertyDescriptor = require('../helpers/isPropertyDescriptor');
- var IsArray = require('./IsArray');
- var IsAccessorDescriptor = require('./IsAccessorDescriptor');
- var IsDataDescriptor = require('./IsDataDescriptor');
- var OrdinaryDefineOwnProperty = require('./OrdinaryDefineOwnProperty');
- var OrdinaryGetOwnProperty = require('./OrdinaryGetOwnProperty');
- var ToNumber = require('./ToNumber');
- var ToString = require('./ToString');
- var ToUint32 = require('./ToUint32');
- var Type = require('./Type');
- // https://262.ecma-international.org/6.0/#sec-arraysetlength
- // eslint-disable-next-line max-statements, max-lines-per-function
- module.exports = function ArraySetLength(A, Desc) {
- if (!IsArray(A)) {
- throw new $TypeError('Assertion failed: A must be an Array');
- }
- if (!isPropertyDescriptor({
- Type: Type,
- IsDataDescriptor: IsDataDescriptor,
- IsAccessorDescriptor: IsAccessorDescriptor
- }, Desc)) {
- throw new $TypeError('Assertion failed: Desc must be a Property Descriptor');
- }
- if (!('[[Value]]' in Desc)) {
- return OrdinaryDefineOwnProperty(A, 'length', Desc);
- }
- var newLenDesc = assign({}, Desc);
- var newLen = ToUint32(Desc['[[Value]]']);
- var numberLen = ToNumber(Desc['[[Value]]']);
- if (newLen !== numberLen) {
- throw new $RangeError('Invalid array length');
- }
- newLenDesc['[[Value]]'] = newLen;
- var oldLenDesc = OrdinaryGetOwnProperty(A, 'length');
- if (!IsDataDescriptor(oldLenDesc)) {
- throw new $TypeError('Assertion failed: an array had a non-data descriptor on `length`');
- }
- var oldLen = oldLenDesc['[[Value]]'];
- if (newLen >= oldLen) {
- return OrdinaryDefineOwnProperty(A, 'length', newLenDesc);
- }
- if (!oldLenDesc['[[Writable]]']) {
- return false;
- }
- var newWritable;
- if (!('[[Writable]]' in newLenDesc) || newLenDesc['[[Writable]]']) {
- newWritable = true;
- } else {
- newWritable = false;
- newLenDesc['[[Writable]]'] = true;
- }
- var succeeded = OrdinaryDefineOwnProperty(A, 'length', newLenDesc);
- if (!succeeded) {
- return false;
- }
- while (newLen < oldLen) {
- oldLen -= 1;
- // eslint-disable-next-line no-param-reassign
- var deleteSucceeded = delete A[ToString(oldLen)];
- if (!deleteSucceeded) {
- newLenDesc['[[Value]]'] = oldLen + 1;
- if (!newWritable) {
- newLenDesc['[[Writable]]'] = false;
- OrdinaryDefineOwnProperty(A, 'length', newLenDesc);
- return false;
- }
- }
- }
- if (!newWritable) {
- return OrdinaryDefineOwnProperty(A, 'length', { '[[Writable]]': false });
- }
- return true;
- };
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