Determining whether one array contains the contents of another array in JavaScript/CoffeeScript

Question

In JavaScript, how do I test that one array has the elements of another array?

arr1 = [1, 2, 3, 4, 5]
[8, 1, 10, 2, 3, 4, 5, 9].function_name(arr1) # => t         


        

Answer 1

You can use array.indexOf():

pseudocode:

function arrayContainsAnotherArray(needle, haystack){
  for(var i = 0; i < needle.length; i++){
    if(haystack.indexOf(needle[i]) === -1)
       return false;
  }
  return true;
}