conditional rest spread

conditionalRestSpread.ts

const oldConcat = Array.prototype.concat;
Array.prototype.concat = function (...args) {
  return oldConcat.apply(this, args.map(x => x == null ? [] : x))
}

// now this works
// Note: only works when actually transpiling to [1,2,3].concat(false && [4,5,6])
//    does not actually work in chrome console

const some = [
  1,
  2,
  3,
  ...false && [4,5,6]
]
// some = [1,2,3]