freeCodeCamp/curriculum/challenges/english/02-javascript-algorithms-and-data-structures/basic-algorithm-scripting/boo-who.english.md

id, title, isRequired, challengeType, forumTopicId

id	title	isRequired	challengeType	forumTopicId
a77dbc43c33f39daa4429b4f	Boo who	true	5	16000

Description

Check if a value is classified as a boolean primitive. Return true or false. Boolean primitives are true and false.

Instructions

Tests

tests:
  - text: <code>booWho(true)</code> should return true.
    testString: assert.strictEqual(booWho(true), true);
  - text: <code>booWho(false)</code> should return true.
    testString: assert.strictEqual(booWho(false), true);
  - text: <code>booWho([1, 2, 3])</code> should return false.
    testString: assert.strictEqual(booWho([1, 2, 3]), false);
  - text: <code>booWho([].slice)</code> should return false.
    testString: assert.strictEqual(booWho([].slice), false);
  - text: '<code>booWho({ "a": 1 })</code> should return false.'
    testString: 'assert.strictEqual(booWho({ "a": 1 }), false);'
  - text: <code>booWho(1)</code> should return false.
    testString: assert.strictEqual(booWho(1), false);
  - text: <code>booWho(NaN)</code> should return false.
    testString: assert.strictEqual(booWho(NaN), false);
  - text: <code>booWho("a")</code> should return false.
    testString: assert.strictEqual(booWho("a"), false);
  - text: <code>booWho("true")</code> should return false.
    testString: assert.strictEqual(booWho("true"), false);
  - text: <code>booWho("false")</code> should return false.
    testString: assert.strictEqual(booWho("false"), false);

Challenge Seed

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

booWho(null);

Solution

function booWho(bool) {
  return typeof bool === "boolean";
}

booWho(null);