how to check if an array contains a string code example

Example 1: how to check if item is in list js

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

Example 2: check if array contain the all element javascript

const myArray: number[] = [2, 4, 6, 8, 10, 12, 14, 16];
const elements: number[] = [4, 8, 12, 16];

function containsAll(arr: number[]) {
  return (
    arr.includes(elements[0]) &&
    arr.includes(elements[1]) &&
    arr.includes(elements[2]) &&
    arr.includes(elements[3])
  );
}
console.log(containsAll(myArray));

or you could use the following line:

function c2(arr: number[]) {
  return elements.every((val: number) => arr.includes(val));
}

Example 3: how to Check if an array contains a string

// To check if an array contains a string 

const colors = ['red', 'green', 'blue'];
const result = colors.includes('red');

console.log(result); // true

// Or 

const colors = ['Red', 'GREEN', 'Blue'];
const result = colors.map(e => e.toLocaleLowerCase())
                     .includes('green');                          

console.log(result); // true