54 lines
1.6 KiB
JavaScript
54 lines
1.6 KiB
JavaScript
|
'use strict';
|
||
|
|
|
||
|
|
var GetIntrinsic = require('get-intrinsic');
|
||
|
|
|
||
|
|
var $ArrayPrototype = GetIntrinsic('%Array.prototype%');
|
||
|
|
var $RangeError = GetIntrinsic('%RangeError%');
|
||
|
|
var $SyntaxError = GetIntrinsic('%SyntaxError%');
|
||
|
|
var $TypeError = GetIntrinsic('%TypeError%');
|
||
|
|
|
||
|
|
var IsInteger = require('./IsInteger');
|
||
|
|
|
||
|
|
var MAX_ARRAY_LENGTH = Math.pow(2, 32) - 1;
|
||
|
|
|
||
|
|
var $setProto = GetIntrinsic('%Object.setPrototypeOf%', true) || (
|
||
|
|
// eslint-disable-next-line no-proto, no-negated-condition
|
||
|
|
[].__proto__ !== $ArrayPrototype
|
||
|
|
? null
|
||
|
|
: function (O, proto) {
|
||
|
|
O.__proto__ = proto; // eslint-disable-line no-proto, no-param-reassign
|
||
|
|
return O;
|
||
|
|
}
|
||
|
|
);
|
||
|
|
|
||
|
|
// https://ecma-international.org/ecma-262/6.0/#sec-arraycreate
|
||
|
|
|
||
|
|
module.exports = function ArrayCreate(length) {
|
||
|
|
if (!IsInteger(length) || length < 0) {
|
||
|
|
throw new $TypeError('Assertion failed: `length` must be an integer Number >= 0');
|
||
|
|
}
|
||
|
|
if (length > MAX_ARRAY_LENGTH) {
|
||
|
|
throw new $RangeError('length is greater than (2**32 - 1)');
|
||
|
|
}
|
||
|
|
var proto = arguments.length > 1 ? arguments[1] : $ArrayPrototype;
|
||
|
|
var A = []; // steps 5 - 7, and 9
|
||
|
|
if (proto !== $ArrayPrototype) { // step 8
|
||
|
|
if (!$setProto) {
|
||
|
|
throw new $SyntaxError('ArrayCreate: a `proto` argument that is not `Array.prototype` is not supported in an environment that does not support setting the [[Prototype]]');
|
||
|
|
}
|
||
|
|
$setProto(A, proto);
|
||
|
|
}
|
||
|
|
if (length !== 0) { // bypasses the need for step 2
|
||
|
|
A.length = length;
|
||
|
|
}
|
||
|
|
/* step 10, the above as a shortcut for the below
|
||
|
|
OrdinaryDefineOwnProperty(A, 'length', {
|
||
|
|
'[[Configurable]]': false,
|
||
|
|
'[[Enumerable]]': false,
|
||
|
|
'[[Value]]': length,
|
||
|
|
'[[Writable]]': true
|
||
|
|
});
|
||
|
|
*/
|
||
|
|
return A;
|
||
|
|
};
|