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

id	title	isRequired	challengeType
af2170cad53daa0770fabdea	Mutations	true	5

Description

Return true if the string in the first element of the array contains all of the letters of the string in the second element of the array. For example, ["hello", "Hello"], should return true because all of the letters in the second string are present in the first, ignoring case. The arguments ["hello", "hey"] should return false because the string "hello" does not contain a "y". Lastly, ["Alien", "line"], should return true because all of the letters in "line" are present in "Alien". Remember to use Read-Search-Ask if you get stuck. Write your own code.

Instructions

Tests

tests:
  - text: <code>mutation(["hello", "hey"])</code> should return false.
    testString: assert(mutation(["hello", "hey"]) === false, '<code>mutation(["hello", "hey"])</code> should return false.');
  - text: <code>mutation(["hello", "Hello"])</code> should return true.
    testString: assert(mutation(["hello", "Hello"]) === true, '<code>mutation(["hello", "Hello"])</code> should return true.');
  - text: <code>mutation(["zyxwvutsrqponmlkjihgfedcba", "qrstu"])</code> should return true.
    testString: assert(mutation(["zyxwvutsrqponmlkjihgfedcba", "qrstu"]) === true, '<code>mutation(["zyxwvutsrqponmlkjihgfedcba", "qrstu"])</code> should return true.');
  - text: <code>mutation(["Mary", "Army"])</code> should return true.
    testString: assert(mutation(["Mary", "Army"]) === true, '<code>mutation(["Mary", "Army"])</code> should return true.');
  - text: <code>mutation(["Mary", "Aarmy"])</code> should return true.
    testString: assert(mutation(["Mary", "Aarmy"]) === true, '<code>mutation(["Mary", "Aarmy"])</code> should return true.');
  - text: <code>mutation(["Alien", "line"])</code> should return true.
    testString: assert(mutation(["Alien", "line"]) === true, '<code>mutation(["Alien", "line"])</code> should return true.');
  - text: <code>mutation(["floor", "for"])</code> should return true.
    testString: assert(mutation(["floor", "for"]) === true, '<code>mutation(["floor", "for"])</code> should return true.');
  - text: <code>mutation(["hello", "neo"])</code> should return false.
    testString: assert(mutation(["hello", "neo"]) === false, '<code>mutation(["hello", "neo"])</code> should return false.');
  - text: <code>mutation(["voodoo", "no"])</code> should return false.
    testString: assert(mutation(["voodoo", "no"]) === false, '<code>mutation(["voodoo", "no"])</code> should return false.');

Challenge Seed

function mutation(arr) {
  return arr;
}

mutation(["hello", "hey"]);

Solution

function mutation(arr) {
  let hash = Object.create(null);

  arr[0].toLowerCase().split('').forEach(c => hash[c] = true);

  return !arr[1].toLowerCase().split('').filter(c => !hash[c]).length;
}

mutation(["hello", "hey"]);