Question

In Javascript, I have 2 arrays of 15 string elements, each of 0 to 17 characters.

How can I tell if one of the values of the first of these two arrays has a value equal to one of the values of the second array?

Example:

var array1 = ['a','b','c','d','e','f','g','h','i','j','k','l','m','n','o'];
var array2 = ['z','z','z','z','z','z','z','z','z','z','z','z','z','o','z'];
myFunction(array1,array2); // returns false

Example 2:

var array1 = ['a','b','c','d','e','f','g','h','i','j','k','l','m','n','s'];
var array2 = ['z','z','z','z','z','z','z','z','z','z','z','z','z','o','z'];
myFunction(array1,array2); // returns true

Answer 1

Eric J.’s suggestion of an intersection is probably most elegant way to approach the problem.

A straightforward translation of what you’re asking could work like this:

function containsAny(array1, array2) {
  for (var i=0; i<array1.length; i++) {
      for (var j=0; j<array2.length; j++) {
          if (array1[i] == array2[j]) return true;
      }
  }
  return false;
}

var array1 = ['a','b','c'];
var array2 = ['1','2','3'];
var array3 = ['a','b','2'];

containsAny(array1, array2); // returns false
containsAny(array2, array3); // returns true 
containsAny(array1, array3); // returns true