code: function _revealMasks(diff) {
      for (var i = 0; i < diff.length; i++) {
          var currPart = diff[i];
  
          if (!_isDiffPart(currPart)) continue;
  
          var prevPart = diff[i - 1],
              nextPart = diff[i + 1],
              matchedMask = currPart.value.match(MASK_REGEXP);
  
          if (!matchedMask) continue;
  
          var regExp = new RegExp('^' +
              matchedMask[1].replace(specialСhars, '\\$1') +
                  matchedMask[2] +
                      matchedMask[3].replace(specialСhars, '\\$1') + '$');
  
          if (currPart.added && nextPart && nextPart.removed) {
              if (nextPart.value.match(regExp)) {
                  nextPart.removed = undefined;
                  diff.splice(i--, 1);
              }
          } else if (currPart.removed && prevPart && prevPart.added) {
              if (prevPart.value.match(regExp)) {
                  prevPart.added = undefined;
                  diff.splice(i--, 1);
              }
          }
      }
  
      return diff;
  }
docs: Removes diff parts which are equal by mask
  @param {Diff[]} diff
  @returns {Diff[]}