code: function fill(list, value, startIndex=0, endIndex=list.length){
      if (!(list && Array.isArray(list))) {
        // Manually currying
        let args = arguments;
        return (list) => fill(list, ...args);
      }
  
      return Array(...list).map((x,i)=> {
        if(i>= startIndex && i <= endIndex) {
          return x=value;
        } else {
          return x;
        }
      });
    }
docs: Fills array using specified values.
  Can optionally pass in start and index of array to fill.
  Default startIndex = 0. Default endIndex = length of array.