in_array in javascript code example

Example 1: js in_array

var a = [1, 2, 3];
a.includes(2); // true 
a.includes(4); // false

Example 2: check items in array javascript

function checkAllEven(arr) {
  return arr.every(function(x){
	 return	x % 2 === 0
	})
}

//using "every" to check every item in array.

Example 3: js inarray

array.includes(élémentRecherché)
array.includes(élémentRecherché, indiceDépart)