const values = [null, undefined, '', 0, false, NaN];
const results = [];

for (let val of values) {
  results.push({
    value: val,
    boolean: !!val,
    string: String(val),
    number: Number(val)
  });
}

console.log(results[2].boolean);
console.log(results[3].string);
console.log(results[1].number);