11th.js

/* DESCRIPTION:
You are given a string of n lines, each substring being n characters long. For example:

s = "abcd\nefgh\nijkl\nmnop"

We will study the "horizontal" and the "vertical" scaling of this square of strings.

A k-horizontal scaling of a string consists of replicating k times each character of the string (except '\n').

Example: 2-horizontal scaling of s: => "aabbccdd\neeffgghh\niijjkkll\nmmnnoopp"
A v-vertical scaling of a string consists of replicating v times each part of the squared string.

Example: 2-vertical scaling of s: => "abcd\nabcd\nefgh\nefgh\nijkl\nijkl\nmnop\nmnop"
Function scale(strng, k, v) will perform a k-horizontal scaling and a v-vertical scaling.

Example: a = "abcd\nefgh\nijkl\nmnop"
scale(a, 2, 3) --> "aabbccdd\naabbccdd\naabbccdd\neeffgghh\neeffgghh\neeffgghh\niijjkkll\niijjkkll\niijjkkll\nmmnnoopp\nmmnnoopp\nmmnnoopp"
Printed:

abcd   ----->   aabbccdd
efgh            aabbccdd
ijkl            aabbccdd
mnop            eeffgghh
                eeffgghh
                eeffgghh
                iijjkkll
                iijjkkll
                iijjkkll
                mmnnoopp
                mmnnoopp
                mmnnoopp
Task:
Write function scale(strng, k, v) k and v will be positive integers. If strng == "" return "". */


const Helper = function(k, n) {
    const SPLIT_IDENTIFIER = '\n';
  
    const repeatWord = (word, times, identifier) => {
      if(word === SPLIT_IDENTIFIER) {
        return word;
      }
      
      return new Array(times).join('x,').split(',').map(x => word).join(identifier);
    };
    
    const repeat = (word, x, identifier) => {
      return word.split(identifier).map(char => repeatWord(char, x, identifier)).join(identifier);
    };
    
    return {
      repeat:function(word) {
        return repeat(repeat(word, n, SPLIT_IDENTIFIER),k,'');
      }
    };
  }
  
  function scale(strng, k, n) {
    const SPLIT_IDENTIFIER = '\n';
    const helper = new Helper(k, n);
    
    if(strng === '') {
      return '';
    }
    
    return strng.split(SPLIT_IDENTIFIER).map(helper.repeat).join(SPLIT_IDENTIFIER);
  }