I don't understand freecodecamp challenge using objects for lookups

Question

I have a JavaScript challenge in freecodecamp that is probably really simple, but I still don't understand how to do it. It goes as follows:

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

  // Only change code below this line
  switch(val) {
case "alpha": 
  result = "Adams";
  break;
case "bravo": 
  result = "Boston";
  break;
case "charlie": 
  result = "Chicago";
  break;
case "delta": 
  result = "Denver";
  break;
case "echo": 
  result = "Easy";
  break;
case "foxtrot": 
  result = "Frank";
  }

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

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

and it wants me to work out a way to look up any of the objects. I'm sure it's not a hard code, but I don't understand the explanation they give and no matter what I do, it still doesn't work and will come up with an 'Expected an assignment or function call and instead saw an expression' which is really annoying. I am not allowed to use switch, case or if statements. Pls help.

Answer 1

You will want to covert the switch statement into an object:

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

Now that you have an object with keys and values you can get a values by using the key like this:

lookup['charlie'] //which will = 'Chicago'

lookup['echo'] //which will = 'Easy'

Since the key will be passed into the function as val you can now use the val to get the correct values associated with the key passed in.

return lookup[val]