given a telephone number, return a list of possible mnemonics using a standard US telephone

phone-number-mnemonics-iteratively.js

const phoneNumberMnemonics = (phoneNumber) => {
  const letters = ["0", "1", "abc", "def", "ghi", "jkl", "mno", "pqrs", "tuv", "wxyz"]
  const numbers = phoneNumber.split('');
  const results = [];
  const wipStack = [
    { wip: '', remaining: numbers }
  ];
  while (wipStack.length > 0) {
    let [wip, remainingNumbers] = wipStack.pop();
    if (remainingNumbers.length > 0) {
      let number = remainingNumbers.pop();
      letters[number].forEach((letter) => {
        wipStack.push({
          wip: wip + letter,
          remaining: remainingNumbers.slice();
        })
      });
    } else {
      results.push(wip);
    }
  }
  return results;
}