Checking for an array in JavaScript

There is a special method Array.isArray that can be used to check whether a variable contains a real array or not. Let's test the method.

An array:

javascriptlet test = [1, 2, 3];
let res  = Array.isArray(test);

console.log(res); // shows true

An object:

javascriptlet test = {a: 1, b: 2, c: 3};
let res  = Array.isArray(test);

console.log(res); // shows false

A primitive:

javascriptlet test = 'abcde';
let res  = Array.isArray(test);

console.log(res); // shows false

A pseudo-array:

javascriptlet test = document.querySelectorAll('p');
let res  = Array.isArray(test);

console.log(res); // shows false

javascriptlet test = [
  [1, 2, 3],
  {a: 1, b: 2, c: 3},
  [3, 4, 5],
  {x: 1, y: 2, z: 3},
];