freeCodeCamp Challenge Guide: Boo who

Guide
1

Boo Who

Problem Explanation

This program is very simple, the trick is to understand what a boolean primitive is. The programs requires a true or false answer.

Relevant Links

Hints

Hint 1

You will need to check for the type of the parameter to see if it is a boolean.

Hint 2

To check for the type of a parameter, you can use typeof.

Hint 3

Since you must return true or false you can use if statements or just have it return the boolean used for the if statement.

Solutions

Solution 1 (Click to Show/Hide) 
function booWho(bool) {
  return typeof bool === "boolean";
}

// test here
booWho(null);

Code Explanation

  • Uses the operator typeof to check if the variable is a boolean. If it is, it will return true. Otherwise, if it is any other type it will return false.

Relevant Links

57 Likes
4

Why not this way?

function booWho(bool) {
  return (bool === true || bool === false);
}
72 Likes
5

Can be performed using the builtin Boolean Function - only primitives remain equal to themselves with all other values converted to a booleans.

function booWho(bool) {

  return Boolean(bool)===bool;
}
13 Likes
6

I did this beautiful piece of work:

  if(bool === false){
    return true;
  }
  return bool === true;
}
33 Likes
7

I wrote more code than necessary at first. Here was my initial code:

function booWho(bool) {
if(typeof(bool) === “boolean”){
return true;
} else {
return false;
}
}

I realized the if statement is unnecessary, because the strict equality operator returns a true or false.

13 Likes
8

Did exactly the same thing (smh):stuck_out_tongue_winking_eye:

9 

function booWho(bool) {
  if (bool === true || bool === false){
    return true;
  }
  else{
    return false; 
  }
}

booWho(null);
33 Likes
10

intermediate?? Shhmmmehh :stuck_out_tongue :stuck_out_tongue:

function booWho(bool) {
  var res = (bool === true || bool === false) ? (true) : (false);
  return res;
}
7 Likes
11

I wish we had haha reactions…

7 Likes
12

I made it like this:

function booWho(bool) {
  // What is the new fad diet for ghost developers? The Boolean.
    return bool === true || bool === false;
}

booWho(null);
7 Likes
13 
function booWho(bool) {
  // What is the new fad diet for ghost developers? The Boolean.
 
  return !!bool === bool;
}

booWho(null);
6 Likes
14

Thought I was pretty clever to come up with my simple solution until I realised it was supposed to be a simple answer:(

function booWho(bool) {
  // What is the new fad diet for gho
  if (typeof bool !== "boolean"){ return false;}
  return true;
}

booWho(null);
6 Likes
15

I didn’t remember that typeof returned a string, so I couldn’t figure out the suggested solution.
Instead I did something a little overly complicated,

function booWho(bool) {
  let test = true;
  return typeof bool === typeof test;
}
5 Likes
16

function booWho(bool) {
return typeof(bool) === “boolean”;
}
booWho(false);

2 Likes
17 
  function booWho(bool) {
  // What is the new fad diet for ghost developers? The Boolean.
  if(typeof(bool)==="boolean"){
    return true;
  }
   else{
     return false;
   }
}
booWho(null);
1 Like
18

I did the exact same thing, too!

19

A very basic solution is to check if the input is one of true or false

function booWho(bool) {
return ([true,false].indexOf(bool) > -1);
}

3 Likes
20

This one was pretty easy. Although some of these other answers are pretty genius.

function booWho(bool) {
var thingy = Boolean(bool);
if (bool !== thingy){return false;}
return true;
}

booWho(false);

1 Like