2048-moveUpTry2.js

2048-moveUpTry2.js

/**
 * @param line Array Old board array
 * @param result New array with new state. Start empty
 * @param lineWithoutZerosMemoized array list of numbers in line without 0
 */
const moveLineUp = (line, results=[], lineWithoutZerosMemoized=null) => {
  // line is used like a counter to add in results
  if(line.length === 0) return results; // If line is empty, get out recursion

  const lineWithoutZeros = lineWithoutZerosMemoized || line.filter((n)=>n > 0);

  if (lineWithoutZeros.length === 0) {
    return moveLineUp(line.slice(1), [...results, 0], []); // Add 0 and remove one in array
  }

  const [currentValue, ...tail] = lineWithoutZeros; // <----- Head and Tail
  if(currentValue === lineWithoutZeros[1]) {
    return moveLineUp(line.slice(1), [...results, currentValue + lineWithoutZeros[1]], lineWithoutZeros.slice(2)); // Remove 2 in lineWithoutZeros, because two blocks joined in one
  }

  return moveLineUp(line.slice(1), [...results, lineWithoutZeros[0]], tail); // Add number and slice line and lineWithoutZeros
};