text: /**
   * @param {string} currentState
   * @return {string[]}
   */
  var generatePossibleNextMoves = function(currentState) {
      // base case
      if(currentState.length <= 1) return [];
      
      let result = [];
      
      for(let i = 0; i < currentState.length; i++) {
          if(i + 1 < currentState.length) {
              if(currentState[i] === '+' && currentState[i + 1] === '+') {
                  result.push(currentState.slice(0, i) + '--' + currentState.slice(i + 2))
              }
          }
      }
      return result;
  };
  