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

id	title	isRequired	challengeType
adf08ec01beb4f99fc7a68f2	Falsy Bouncer	true	5

Description

Remove all falsy values from an array. Falsy values in JavaScript are false, null, 0, "", undefined, and NaN. Hint: Try converting each value to a Boolean. Remember to use Read-Search-Ask if you get stuck. Write your own code.

Instructions

Tests

tests:
  - text: <code>bouncer([7, "ate", "", false, 9])</code> should return <code>[7, "ate", 9]</code>.
    testString: assert.deepEqual(bouncer([7, "ate", "", false, 9]), [7, "ate", 9], '<code>bouncer([7, "ate", "", false, 9])</code> should return <code>[7, "ate", 9]</code>.');
  - text: <code>bouncer(["a", "b", "c"])</code> should return <code>["a", "b", "c"]</code>.
    testString: assert.deepEqual(bouncer(["a", "b", "c"]), ["a", "b", "c"], '<code>bouncer(["a", "b", "c"])</code> should return <code>["a", "b", "c"]</code>.');
  - text: <code>bouncer([false, null, 0, NaN, undefined, ""])</code> should return <code>[]</code>.
    testString: assert.deepEqual(bouncer([false, null, 0, NaN, undefined, ""]), [], '<code>bouncer([false, null, 0, NaN, undefined, ""])</code> should return <code>[]</code>.');
  - text: <code>bouncer([1, null, NaN, 2, undefined])</code> should return <code>[1, 2]</code>.
    testString: assert.deepEqual(bouncer([1, null, NaN, 2, undefined]), [1, 2], '<code>bouncer([1, null, NaN, 2, undefined])</code> should return <code>[1, 2]</code>.');

Challenge Seed

function bouncer(arr) {
  // Don't show a false ID to this bouncer.
  return arr;
}

bouncer([7, "ate", "", false, 9]);

Solution

function bouncer(arr) {
  return arr.filter(e => e);
}

bouncer([7, "ate", "", false, 9]);