JavaScript: Array-Like Object

What is a array-like object

A object such that is all of the following:

• Has property names of consecutive non-negative integers {"0", "1", "2", etc}.
• Has a property "length" with a value that's the count of these properties, and typically it has the Enumerable attribute false.
• Is not a true array. That is, Array.isArray(obj) returns false.

Create a Array-Like Object

// create a array-like object
let xx = { 0: "a", 1: "b", length: 2 };

Reflect.defineProperty(xx, "length", { enumerable: false });

console.log(xx.propertyIsEnumerable("length") === false);

Difference Between Array vs Array-Like Object

• Difference Between Array vs Array-Like Object

Check if a object is true array

• Array.isArray

Where does array-like object came from

• In DOM, method such as document.getElementsByClassName return array-like objects. [see Get Element by ID, Name, Class etc]
• function arguments Object is a array-like object.

Apply Array Method to Array-Like Object

• Apply Array Method to Array-Like Object

Convert array-like object to array

• Array-Like Object to Array

Get Property Values of Array-Like Object

• List Properties