package.2021.IsValidIntegerIndex.js Maven / Gradle / Ivy

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ECMAScript spec abstract operations.

There is a newer version: 1.22.3

'use strict';

var GetIntrinsic = require('get-intrinsic');

var $TypeError = GetIntrinsic('%TypeError%');

var IsDetachedBuffer = require('./IsDetachedBuffer');
var IsIntegralNumber = require('./IsIntegralNumber');

var isNegativeZero = require('../helpers/isNegativeZero');

var typedArrayBuffer = require('typed-array-buffer');

// https://262.ecma-international.org/12.0/#sec-isvalidintegerindex

module.exports = function IsValidIntegerIndex(O, index) {
	// Assert: O is an Integer-Indexed exotic object.
	var buffer = typedArrayBuffer(O); // step 1

	if (typeof index !== 'number') {
		throw new $TypeError('Assertion failed: Type(index) is not Number');
	}

	if (IsDetachedBuffer(buffer)) { return false; } // step 2

	if (!IsIntegralNumber(index)) { return false; } // step 3

	if (isNegativeZero(index)) { return false; } // step 4

	if (index < 0 || index >= O.length) { return false; } // step 5

	return true; // step 6
};