Check if array contains all elements of another array

Question

I want a function that returns true if and only if a given array includes all the elements of a given "target" array. As follows.

const         


        

Answer 1

You can try with Array.prototype.every():

The every() method tests whether all elements in the array pass the test implemented by the provided function.

and Array.prototype.includes():

The includes() method determines whether an array includes a certain element, returning true or false as appropriate.

var mainArr = [1,2,3];
function isTrue(arr, arr2){
  return arr.every(i => arr2.includes(i));
}
console.log(isTrue(mainArr, [1,2,3]));
console.log(isTrue(mainArr, [1,2,3,4]));
console.log(isTrue(mainArr, [1,2]));