securityos/node_modules/es-abstract/2021/IntegerIndexedElementGet.js

40 lines
1.2 KiB
JavaScript

'use strict';
var $TypeError = require('es-errors/type');
var GetValueFromBuffer = require('./GetValueFromBuffer');
var IsValidIntegerIndex = require('./IsValidIntegerIndex');
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/12.0/#sec-integerindexedelementget
module.exports = function IntegerIndexedElementGet(O, index) {
var arrayTypeName = whichTypedArray(O); // step 4
if (!arrayTypeName) {
throw new $TypeError('Assertion failed: `O` must be a TypedArray'); // step 1
}
if (typeof index !== 'number') {
throw new $TypeError('Assertion failed: `index` must be a Number');
}
if (!IsValidIntegerIndex(O, index)) {
return void undefined; // step 2
}
var offset = typedArrayByteOffset(O); // step 3
var elementType = tableTAO.name['$' + arrayTypeName]; // step 7
var elementSize = tableTAO.size['$' + elementType]; // step 5
var indexedPosition = (index * elementSize) + offset; // step 6
return GetValueFromBuffer(typedArrayBuffer(O), indexedPosition, elementType, true, 'Unordered'); // step 11
};