securityos/node_modules/es-abstract/2020/IntegerIndexedElementGet.js

54 lines
1.5 KiB
JavaScript

'use strict';
var $TypeError = require('es-errors/type');
var GetValueFromBuffer = require('./GetValueFromBuffer');
var IsDetachedBuffer = require('./IsDetachedBuffer');
var IsValidIntegerIndex = require('./IsValidIntegerIndex');
var typedArrayLength = require('typed-array-length');
var typedArrayBuffer = require('typed-array-buffer');
var typedArrayByteOffset = require('typed-array-byte-offset');
var whichTypedArray = require('which-typed-array');
var tableTAO = require('./tables/typed-array-objects');
// https://262.ecma-international.org/11.0/#sec-integerindexedelementget
module.exports = function IntegerIndexedElementGet(O, index) {
var arrayTypeName = whichTypedArray(O); // step 7
if (!arrayTypeName) {
throw new $TypeError('`O` must be a TypedArray'); // step 1
}
if (typeof index !== 'number') {
throw new $TypeError('`index` must be a Number'); // step 2
}
var buffer = typedArrayBuffer(O); // step 3
if (IsDetachedBuffer(buffer)) {
throw new $TypeError('`O` has a detached buffer'); // step 4
}
if (!IsValidIntegerIndex(O, index)) {
return void undefined; // step 5
}
var offset = typedArrayByteOffset(O); // step 6
var length = typedArrayLength(O); // step 7
if (index < 0 || index >= length) {
return void undefined; // step 8
}
var elementType = tableTAO.name['$' + arrayTypeName]; // step 10
var elementSize = tableTAO.size['$' + elementType]; // step 8
var indexedPosition = (index * elementSize) + offset; // step 9
return GetValueFromBuffer(buffer, indexedPosition, elementType, true, 'Unordered'); // step 11
};