if element in array javascript code example

Example 1: javascript array contains

var colors = ["red", "blue", "green"];
var hasRed = colors.includes("red"); //true
var hasYellow = colors.includes("yellow"); //false

Example 2: javascript element in array

var fruits = ["Banana", "Orange", "Apple", "Mango"];

var n = fruits.includes("Mango");

Example 3: how to check if item is in list js

var myList=["a", "b", "c"];
mylist.includes("d")//returns true or false

Example 4: not in array js

!array.includes("element")

Example 5: javascript check if in array

var extensions = ["image/jpeg","image/png","image/gif"];          
if(extensions.indexOf("myfiletype") === -1){
	alert("Image must be .png, .jpg or .gif");
}

Example 6: 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.