How to know if two arrays have the same values

Question

I have these two arrays: one is filled with information from an ajax request and another stores the buttons the user clicks on. I use this code (I filled with sample numbers):

var array1 = [2, 4];
var array2 = [4, 2]; //It cames from the user button clicks, so it might be disordered.
array1.sort(); //Sorts both Ajax and user info.
array2.sort();
if (array1==array2) {
    doSomething();
}else{
    doAnotherThing();
}

But it always gives false, even if the two arrays are the same, but with different name. (I checked this in Chrome's JS Console). So, is there any way I could know if these two arrays contain the same? Why is it giving false? How can I know which values in the first array are not in the second?

Answer 1

Sort the arrays and compare their values one by one.

function arrayCompare(_arr1, _arr2) {
    if (
      !Array.isArray(_arr1)
      || !Array.isArray(_arr2)
      || _arr1.length !== _arr2.length
      ) {
        return false;
      }
    
    // .concat() to not mutate arguments
    const arr1 = _arr1.concat().sort();
    const arr2 = _arr2.concat().sort();
    
    for (let i = 0; i < arr1.length; i++) {
        if (arr1[i] !== arr2[i]) {
            return false;
         }
    }
    
    return true;
}