8-2-21.js

// The Vowel Code

// Step 1: Create a function called encode() to replace all the lowercase vowels in a given string with numbers according to the following pattern:

// a -> 1
// e -> 2
// i -> 3
// o -> 4
// u -> 5
// For example, encode("hello") would return "h2ll4". There is no need to worry about uppercase vowels in this kata.

// Step 2: Now create a function called decode() to turn the numbers back into vowels according to the same pattern shown above.

// For example, decode("h3 th2r2") would return "hi there".

// For the sake of simplicity, you can assume that any numbers passed into the function will correspond to vowels.

function encode(string) {
    let alph = 'aeiou'
      let vowels = {
      'a': 1,
      'e': 2,
      'i': 3,
      'o': 4,
      'u': 5
    }
      let str = ''
    for (let i = 0 ; i < string.length ; i++) {
      if (alph.includes(string[i])) {
        str += vowels[string[i]]
      } else str += string[i]
    } return str
  }
  
  function decode(string) {
    let nums = [1,2,3,4,5]
      let vowels = {
      'a': 1,
      'e': 2,
      'i': 3,
      'o': 4,
      'u': 5
    }
      let str = ''
    for (let i = 0 ; i < string.length ; i++) {
      if (nums.includes(+string[i])) {
        str += Object.keys(vowels).find(x=>vowels[x] === +string[i])
      } else {
        str += string[i]
      }
    }
    return str
  }