Using Objects for Lookups

JavaScript
1

Tell us what’s happening:
Everything has passed however, i am not sure how to return undefined for phoneticLookup("")

Your code so far


// Setup
function phoneticLookup(val) {
  var result = "";

  // Only change code below this line



  var lookup = {
    'alpha': 'Adams',
    'bravo': 'Boston',
    'charlie': 'Chicago',
    'delta': 'Denver',
    'echo': 'Easy',
    'foxtrot': 'Frank'
  };

result += lookup[val];


  // Only change code above this line
  return result;
}

// Change this value to test
phoneticLookup("charlie");

Your browser information:

User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/77.0.3865.90 Safari/537.36.

Link to the challenge:
https://learn.freecodecamp.org/javascript-algorithms-and-data-structures/basic-javascript/using-objects-for-lookups

2

You can return undefined by

return undefined;

or

return;
3

right but we are not supposed to change the return line

4

You can assign undefined to the variable result.

5

result has been assigned the object with the function parameter

6

Yes, but at no point is result ever undefined;

7

I see, so how would i assign result undefined while maintaining all other output values for result?

8

Right now result is always a string. It starts out as an empty string and your line result += lookup[val] appends to that string. If val is not a property in lookup, then lookup[val] is undefined, but when you append it to an empty string the result is still an empty string.

9

Yes.
Ok, I completely understand.
Because I was appending the result variable, it was maintaining the empty string that it was declared and assigned as and when lookup[val] is undefined, the result variable would still hold the empty string that it was originally declared and assigned with.

Rather than add on to the string as I did when I appended it using += I should have originally just reassigned it the variable

10

Exactly :smiley:

11

Thank you for your help and pointing that out and explaining this to me :smiley:

12

I’m glad that I could help. Happy coding!