Returning true if JavaScript array contains an element

Question

So far I have this code:

var isMatch = viewedUserLikedUsersArray.indexOf(logged_in_user);
    if (isMatch >=0){
      console.log(\'is match\');
    }
    els         


        

Answer 1

At first, we have to understand, what is stored in viewedUserLikedUsersArray array.

If there are primitives, it's ok, but if there are objects we can't use indexOf method of array, because it use strict comparison === inside, how we know, the comparison with object is going by link.

indexOf works similar to iterating through the loop, the only way.

In case with objects we can use find method of array MDN Array.prototype.find() or findIndex Array.prototype.findIndex();

Also we can store users in hashMap with userId keys, and check matching by referring to the object property.

var someUsers = {
  '#124152342': {
    ...
  },
  '#534524235': {
    ...
  },
  ...
};

...

var someUserId = '#124152342';

if (someUsers[someUserId]) {
  console.log('is match');
} else {
  console.log('no match');
}