Solution to Sub-task Line Breaks

// helper function to permute combinations
// input -> [[String][String]] eg. [['he'],['l', 'lo']]
// Output -> [[[String][String]]] 
// eg. [ [['he'], ['l', 'lo']],
//       [['he', 'l'], ['lo']],
//       [['he', 'l', 'lo'], []], ]
function getPermutations(arr){
  let [fst , snd] = arr; // destructure array
  if(snd.length === 0) return [[fst, snd]]; // basecase
  let [x, ...xs] = snd; // remove one element from right arrray
  let permute = [[...fst, x], xs]; // shift removed element to left array
  let answer = getPermutations(permute); // call for further combinations
  return [arr, ...answer]; // return all combinations
}
function lineBreaks(dict, width, line){
  let [fstPart, sndPart] = splitLine(line, width);
  if(sndPart.length === 0) return [[fstPart, sndPart]];
  
  let word = sndPart[0].replace(/[^A-Za-z]/g,''); // get first word of second part of line
  if(dict.hasOwnProperty(word)){
    let permutations = getPermutations([[],dict[word]]);
    // map all permutations with splitLine output
    let possAns = permutations.map(x => {
      // see if hyphen needed
      let leftSide = x[0].length ? x[0].join('').concat('-') : [];
      // see if punctuation mark needed
      let rightSide = sndPart[0].match(/[.,]/) ? 
            x[1].join('') + sndPart[0].substr(-1):
            x[1].join('') ;
      // add leftSide and rightSide
      return leftSide.length? 
        [[ ...fstPart, leftSide],[ rightSide, ...sndPart.slice(1)]]
        : [[ ...fstPart],[ rightSide, ...sndPart.slice(1)]];
    });
    // filter lines with greater than the width length
    let finAns = possAns.filter(x => {
      let total = x[0].reduce((prev, curr) => curr.length + prev, 0);
      return (x[0].length - 1 + total) <= width
    })
    return finAns; // return final answer
  }
  else{
    return [[fstPart, sndPart]];
  }
}
// dictionary
enHyp = {
  "creative" : ["cr","ea","ti","ve"], 
  "controls" : ["co","nt","ro","ls"], 
  "achieve" : ["ach","ie","ve"], 
  "future" : ["fu","tu","re"], 
  "present" : ["pre","se","nt"], 
  "motivated" : ["mot","iv","at","ed"], 
  "desire" : ["de","si","re"], 
  "others" : ["ot","he","rs"],
}
console.log(lineBreaks(enHyp,12, ["He", "who", "controls.","world"] ));