ARRLIKE: Does an object behave like an array?

Installation

npm install arrlike

Usage

arrlike exposes two functions; one is isArrLikePure, and the other is isArrLikeLoose.

isArrLikePure(o: any, requireLength?: bool = false)

isArrLikePure checks whether an object's enumerable keys are a sequence of consecutive integers starting from 0

var isArrLikePure = require('arrlike').isArrLikePure;

isArrLikePure([0]); // true

isArrLikePure({0: 'a', 1: 'b'}); // true

isArrLikePure({0, 'a', 55: 'all right'}); // false -- `0 55` not a consecutiv sequence

isArrLikePure can optionally take a second argument; when true, this argument causes isArrLikePure to only accept objects which have an integer length property and their enumerable keys has a count equal to that length.

var isArrLikePure = require('arrlike').isArrLikePure;

isArrLikePure(['a','b','c','d','e'], true); 
//  true; [1,2,8,40,120]['length'] === 5 and it has 5 enumerable consecutive keys: '0', '1', '2', '3', '4'

isArrLikePure({0: 'a', 1: 'b'}, true);
//  false; {0: 'a', 1: 'b'} has no 'length'

isArrLikePure({0: 'a', 1: 'b', 'length': 2}, true); 
//  false; {0: 'a', 1: 'b', 'length': 2}'s enumerable keys are '0', '1', 'length', which is not a consecutive sequence of integers

isArrLikeLoose(o: any)

isArrLikeLoose is more lenient, and, consequently, more dangerous; it would return true if the list of its argument's enumerable integer keys constitute a consecutive sequence of integers starting from 0. otherwise, particularly when the object has no integer keys, it returns false.

var isArrLikeLoose = require('arrlike').isArrLikeLoose;

// true; enumerable keys are '0','1','2','3','4' which constitute a sequence of consecutive integers starting from 0
isArrLikeLoose(['a', 'b', 'c'. 'd', 'e']);

// true! its enumebrable integer keys constitute a sequence of consecutive integers starting from 0
isArrLike({'a': 'apples', 'b': 'bananas', '0': 'got', '1': 'ya'});

// false
isArrLikeLoose({'a': 'avocados', 'b': 'blueberries', '1': 'not', '500': 'ya'})