Bitty Words.js

/*
Description:
Your friend has given you a secret message nested inside a block of text. She provided you the key to her code as a number and now you must decode the message.

The number, in binary, represents on/off flags for each word of the phrase. The bit order, overlayed on the array of words, will give which words to include in the phrase.

Example:
bittyWords('Long live the king', 11)
Convert to binary: 11 = 0b1011
Apply binary to words list:
['Long', 'live', 'the', 'king']
    1       0      1       1
result: 'Long the king'
If the number does not have enough bits for the words array, left pad the number with 0s.

Example:

bittyWords('So long and thanks for all the fish', 42) === 'and for the'
42 is 0b101010 which is only 6 words, but the phrase has 8 words. The left two words are 0s and not included in the output.

To uncomplicate things, there will be no punctuation in the phrases.
*/
function bittyWords(words, bits) {
  let str = bits.toString(2) 
  let wL=words.split` `.length-str.length
  if (wL>0){
    str='0'.repeat(wL)+str
  }
  return words.split` `.filter((v,i)=>str.toString(2)[i]*1===1).join` `
}