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