a trail for code

solution.js

function resolve(howMany) {
  const arr = new Set();
  //  generate stuff

  function getNumber() {
    return Math.floor(Math.random() * 10000);
  }

  function getFourDigitNum() {
    let pin;
    do {
      pin = getNumber();
    } while (pin <= 1000);
    return pin;
  }

  while (arr.size <= howMany) {
    let pin;
    let stringArr;
    let numArr;
    let isValid;
    do {
      pin = getFourDigitNum();
      const tempArr = pin.toString().split('');
      stringArr = new Set(tempArr);

      numArr = tempArr.map(parseInt);
      isValid =
        numArr[0] - numArr[1] !== 1 &&
        numArr[1] - numArr[2] !== 1 &&
        numArr[2] - numArr[3] !== 1;
    } while (stringArr.size !== 4 && isValid);

    arr.add(pin);
  }

  return arr;
}

console.log(Array.from(resolve(1000)).join(','));