00 parse float.js

// Write function parseF which takes an input and returns a number or null if conversion is not possible. The input can be one of many different types so be aware.

function parseF(s) {
  return s == parseFloat(s)? parseFloat(s) : null
}

// using isNaN()

function parseF(s) {
  const f = parseFloat(s)
  return isNaN(f) ? null : f
}