arrayDiff, createPhoneNumber,

by trentHarlem

JavaScript

//WORKING
const arrayDiff = (a, b) => a.filter(a => b.indexOf(a) === -1)

console.log(arrayDiff([], [4, 5]), [], "a was [], b was [4,5]");
console.log(arrayDiff([3, 4], [3]), [4], "a was [3,4], b was [3]");
console.log(arrayDiff([1, 8, 2], []), [1, 8, 2], "a was [1,8,2], b was []");
//////////////////////////////////////////////////////////

//WORKING
/* function createPhoneNumber(numbers) {
  return `(${numbers.slice(0,3).join('')}) ${numbers.slice(3,6).join('')}-${numbers.slice(6,10).join('')}`
} */

/* function createPhoneNumber(numbers) {
let phoneNum = `(___) ___-____`
 for(let digit of numbers) {
 phoneNum = phoneNum.replace('_',digit)
 }
 return phoneNum
} */

function createPhoneNumber(numbers){
  return numbers.join('').replace(/(\d{3})(\d{3})(\d{4})/,'($1) $2-$3');
}


console.log(createPhoneNumber([1, 2, 3, 4, 5, 6, 7, 8, 9, 0]))