how to check if an array contains a lette js 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: 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));
}