feat: updates & github event support

node_modules/fast-diff/diff.js

@@ -23,7 +23,6 @@
  * limitations under the License.
  */
 
-
 /**
  * The data structure representing a diff is an array of tuples:
  * [[DIFF_DELETE, 'Hello'], [DIFF_INSERT, 'Goodbye'], [DIFF_EQUAL, ' world.']]
@@ -33,16 +32,16 @@ var DIFF_DELETE = -1;
 var DIFF_INSERT = 1;
 var DIFF_EQUAL = 0;
 
-
 /**
  * Find the differences between two texts.  Simplifies the problem by stripping
  * any common prefix or suffix off the texts before diffing.
  * @param {string} text1 Old string to be diffed.
  * @param {string} text2 New string to be diffed.
  * @param {Int|Object} [cursor_pos] Edit position in text1 or object with more info
+ * @param {boolean} [cleanup] Apply semantic cleanup before returning.
  * @return {Array} Array of diff tuples.
  */
-function diff_main(text1, text2, cursor_pos, _fix_unicode) {
+function diff_main(text1, text2, cursor_pos, cleanup, _fix_unicode) {
   // Check for equality
   if (text1 === text2) {
     if (text1) {
@@ -81,9 +80,11 @@ function diff_main(text1, text2, cursor_pos, _fix_unicode) {
     diffs.push([DIFF_EQUAL, commonsuffix]);
   }
   diff_cleanupMerge(diffs, _fix_unicode);
+  if (cleanup) {
+    diff_cleanupSemantic(diffs);
+  }
   return diffs;
-};
-
+}
 
 /**
  * Find the differences between two texts.  Assumes that the texts do not
@@ -113,7 +114,7 @@ function diff_compute_(text1, text2) {
     diffs = [
       [DIFF_INSERT, longtext.substring(0, i)],
       [DIFF_EQUAL, shorttext],
-      [DIFF_INSERT, longtext.substring(i + shorttext.length)]
+      [DIFF_INSERT, longtext.substring(i + shorttext.length)],
     ];
     // Swap insertions for deletions if diff is reversed.
     if (text1.length > text2.length) {
@@ -125,7 +126,10 @@ function diff_compute_(text1, text2) {
   if (shorttext.length === 1) {
     // Single character string.
     // After the previous speedup, the character can't be an equality.
-    return [[DIFF_DELETE, text1], [DIFF_INSERT, text2]];
+    return [
+      [DIFF_DELETE, text1],
+      [DIFF_INSERT, text2],
+    ];
   }
 
   // Check to see if the problem can be split in two.
@@ -145,8 +149,7 @@ function diff_compute_(text1, text2) {
   }
 
   return diff_bisect_(text1, text2);
-};
-
+}
 
 /**
  * Find the 'middle snake' of a diff, split the problem in two
@@ -177,7 +180,7 @@ function diff_bisect_(text1, text2) {
   var delta = text1_length - text2_length;
   // If the total number of characters is odd, then the front path will collide
   // with the reverse path.
-  var front = (delta % 2 !== 0);
+  var front = delta % 2 !== 0;
   // Offsets for start and end of k loop.
   // Prevents mapping of space beyond the grid.
   var k1start = 0;
@@ -196,7 +199,8 @@ function diff_bisect_(text1, text2) {
       }
       var y1 = x1 - k1;
       while (
-        x1 < text1_length && y1 < text2_length &&
+        x1 < text1_length &&
+        y1 < text2_length &&
         text1.charAt(x1) === text2.charAt(y1)
       ) {
         x1++;
@@ -233,8 +237,10 @@ function diff_bisect_(text1, text2) {
       }
       var y2 = x2 - k2;
       while (
-        x2 < text1_length && y2 < text2_length &&
-        text1.charAt(text1_length - x2 - 1) === text2.charAt(text2_length - y2 - 1)
+        x2 < text1_length &&
+        y2 < text2_length &&
+        text1.charAt(text1_length - x2 - 1) ===
+          text2.charAt(text2_length - y2 - 1)
       ) {
         x2++;
         y2++;
@@ -263,9 +269,11 @@ function diff_bisect_(text1, text2) {
   }
   // Diff took too long and hit the deadline or
   // number of diffs equals number of characters, no commonality at all.
-  return [[DIFF_DELETE, text1], [DIFF_INSERT, text2]];
-};
-
+  return [
+    [DIFF_DELETE, text1],
+    [DIFF_INSERT, text2],
+  ];
+}
 
 /**
  * Given the location of the 'middle snake', split the diff in two parts
@@ -287,8 +295,7 @@ function diff_bisectSplit_(text1, text2, x, y) {
   var diffsb = diff_main(text1b, text2b);
 
   return diffs.concat(diffsb);
-};
-
+}
 
 /**
  * Determine the common prefix of two strings.
@@ -326,8 +333,57 @@ function diff_commonPrefix(text1, text2) {
   }
 
   return pointermid;
-};
+}
 
+/**
+ * Determine if the suffix of one string is the prefix of another.
+ * @param {string} text1 First string.
+ * @param {string} text2 Second string.
+ * @return {number} The number of characters common to the end of the first
+ *     string and the start of the second string.
+ * @private
+ */
+function diff_commonOverlap_(text1, text2) {
+  // Cache the text lengths to prevent multiple calls.
+  var text1_length = text1.length;
+  var text2_length = text2.length;
+  // Eliminate the null case.
+  if (text1_length == 0 || text2_length == 0) {
+    return 0;
+  }
+  // Truncate the longer string.
+  if (text1_length > text2_length) {
+    text1 = text1.substring(text1_length - text2_length);
+  } else if (text1_length < text2_length) {
+    text2 = text2.substring(0, text1_length);
+  }
+  var text_length = Math.min(text1_length, text2_length);
+  // Quick check for the worst case.
+  if (text1 == text2) {
+    return text_length;
+  }
+
+  // Start by looking for a single character match
+  // and increase length until no match is found.
+  // Performance analysis: http://neil.fraser.name/news/2010/11/04/
+  var best = 0;
+  var length = 1;
+  while (true) {
+    var pattern = text1.substring(text_length - length);
+    var found = text2.indexOf(pattern);
+    if (found == -1) {
+      return best;
+    }
+    length += found;
+    if (
+      found == 0 ||
+      text1.substring(text_length - length) == text2.substring(0, length)
+    ) {
+      best = length;
+      length++;
+    }
+  }
+}
 
 /**
  * Determine the common suffix of two strings.
@@ -364,8 +420,7 @@ function diff_commonSuffix(text1, text2) {
   }
 
   return pointermid;
-};
-
+}
 
 /**
  * Do the two texts share a substring which is at least half the length of the
@@ -381,7 +436,7 @@ function diff_halfMatch_(text1, text2) {
   var longtext = text1.length > text2.length ? text1 : text2;
   var shorttext = text1.length > text2.length ? text2 : text1;
   if (longtext.length < 4 || shorttext.length * 2 < longtext.length) {
-    return null;  // Pointless.
+    return null; // Pointless.
   }
 
   /**
@@ -400,16 +455,21 @@ function diff_halfMatch_(text1, text2) {
     // Start with a 1/4 length substring at position i as a seed.
     var seed = longtext.substring(i, i + Math.floor(longtext.length / 4));
     var j = -1;
-    var best_common = '';
+    var best_common = "";
     var best_longtext_a, best_longtext_b, best_shorttext_a, best_shorttext_b;
     while ((j = shorttext.indexOf(seed, j + 1)) !== -1) {
       var prefixLength = diff_commonPrefix(
-        longtext.substring(i), shorttext.substring(j));
+        longtext.substring(i),
+        shorttext.substring(j)
+      );
       var suffixLength = diff_commonSuffix(
-        longtext.substring(0, i), shorttext.substring(0, j));
+        longtext.substring(0, i),
+        shorttext.substring(0, j)
+      );
       if (best_common.length < suffixLength + prefixLength) {
-        best_common = shorttext.substring(
-          j - suffixLength, j) + shorttext.substring(j, j + prefixLength);
+        best_common =
+          shorttext.substring(j - suffixLength, j) +
+          shorttext.substring(j, j + prefixLength);
         best_longtext_a = longtext.substring(0, i - suffixLength);
         best_longtext_b = longtext.substring(i + prefixLength);
         best_shorttext_a = shorttext.substring(0, j - suffixLength);
@@ -418,8 +478,11 @@ function diff_halfMatch_(text1, text2) {
     }
     if (best_common.length * 2 >= longtext.length) {
       return [
-        best_longtext_a, best_longtext_b,
-        best_shorttext_a, best_shorttext_b, best_common
+        best_longtext_a,
+        best_longtext_b,
+        best_shorttext_a,
+        best_shorttext_b,
+        best_common,
       ];
     } else {
       return null;
@@ -427,9 +490,17 @@ function diff_halfMatch_(text1, text2) {
   }
 
   // First check if the second quarter is the seed for a half-match.
-  var hm1 = diff_halfMatchI_(longtext, shorttext, Math.ceil(longtext.length / 4));
+  var hm1 = diff_halfMatchI_(
+    longtext,
+    shorttext,
+    Math.ceil(longtext.length / 4)
+  );
   // Check again based on the third quarter.
-  var hm2 = diff_halfMatchI_(longtext, shorttext, Math.ceil(longtext.length / 2));
+  var hm2 = diff_halfMatchI_(
+    longtext,
+    shorttext,
+    Math.ceil(longtext.length / 2)
+  );
   var hm;
   if (!hm1 && !hm2) {
     return null;
@@ -457,8 +528,267 @@ function diff_halfMatch_(text1, text2) {
   }
   var mid_common = hm[4];
   return [text1_a, text1_b, text2_a, text2_b, mid_common];
-};
+}
 
+/**
+ * Reduce the number of edits by eliminating semantically trivial equalities.
+ * @param {!Array.<!diff_match_patch.Diff>} diffs Array of diff tuples.
+ */
+function diff_cleanupSemantic(diffs) {
+  var changes = false;
+  var equalities = []; // Stack of indices where equalities are found.
+  var equalitiesLength = 0; // Keeping our own length var is faster in JS.
+  /** @type {?string} */
+  var lastequality = null;
+  // Always equal to diffs[equalities[equalitiesLength - 1]][1]
+  var pointer = 0; // Index of current position.
+  // Number of characters that changed prior to the equality.
+  var length_insertions1 = 0;
+  var length_deletions1 = 0;
+  // Number of characters that changed after the equality.
+  var length_insertions2 = 0;
+  var length_deletions2 = 0;
+  while (pointer < diffs.length) {
+    if (diffs[pointer][0] == DIFF_EQUAL) {
+      // Equality found.
+      equalities[equalitiesLength++] = pointer;
+      length_insertions1 = length_insertions2;
+      length_deletions1 = length_deletions2;
+      length_insertions2 = 0;
+      length_deletions2 = 0;
+      lastequality = diffs[pointer][1];
+    } else {
+      // An insertion or deletion.
+      if (diffs[pointer][0] == DIFF_INSERT) {
+        length_insertions2 += diffs[pointer][1].length;
+      } else {
+        length_deletions2 += diffs[pointer][1].length;
+      }
+      // Eliminate an equality that is smaller or equal to the edits on both
+      // sides of it.
+      if (
+        lastequality &&
+        lastequality.length <=
+          Math.max(length_insertions1, length_deletions1) &&
+        lastequality.length <= Math.max(length_insertions2, length_deletions2)
+      ) {
+        // Duplicate record.
+        diffs.splice(equalities[equalitiesLength - 1], 0, [
+          DIFF_DELETE,
+          lastequality,
+        ]);
+        // Change second copy to insert.
+        diffs[equalities[equalitiesLength - 1] + 1][0] = DIFF_INSERT;
+        // Throw away the equality we just deleted.
+        equalitiesLength--;
+        // Throw away the previous equality (it needs to be reevaluated).
+        equalitiesLength--;
+        pointer = equalitiesLength > 0 ? equalities[equalitiesLength - 1] : -1;
+        length_insertions1 = 0; // Reset the counters.
+        length_deletions1 = 0;
+        length_insertions2 = 0;
+        length_deletions2 = 0;
+        lastequality = null;
+        changes = true;
+      }
+    }
+    pointer++;
+  }
+
+  // Normalize the diff.
+  if (changes) {
+    diff_cleanupMerge(diffs);
+  }
+  diff_cleanupSemanticLossless(diffs);
+
+  // Find any overlaps between deletions and insertions.
+  // e.g: <del>abcxxx</del><ins>xxxdef</ins>
+  //   -> <del>abc</del>xxx<ins>def</ins>
+  // e.g: <del>xxxabc</del><ins>defxxx</ins>
+  //   -> <ins>def</ins>xxx<del>abc</del>
+  // Only extract an overlap if it is as big as the edit ahead or behind it.
+  pointer = 1;
+  while (pointer < diffs.length) {
+    if (
+      diffs[pointer - 1][0] == DIFF_DELETE &&
+      diffs[pointer][0] == DIFF_INSERT
+    ) {
+      var deletion = diffs[pointer - 1][1];
+      var insertion = diffs[pointer][1];
+      var overlap_length1 = diff_commonOverlap_(deletion, insertion);
+      var overlap_length2 = diff_commonOverlap_(insertion, deletion);
+      if (overlap_length1 >= overlap_length2) {
+        if (
+          overlap_length1 >= deletion.length / 2 ||
+          overlap_length1 >= insertion.length / 2
+        ) {
+          // Overlap found.  Insert an equality and trim the surrounding edits.
+          diffs.splice(pointer, 0, [
+            DIFF_EQUAL,
+            insertion.substring(0, overlap_length1),
+          ]);
+          diffs[pointer - 1][1] = deletion.substring(
+            0,
+            deletion.length - overlap_length1
+          );
+          diffs[pointer + 1][1] = insertion.substring(overlap_length1);
+          pointer++;
+        }
+      } else {
+        if (
+          overlap_length2 >= deletion.length / 2 ||
+          overlap_length2 >= insertion.length / 2
+        ) {
+          // Reverse overlap found.
+          // Insert an equality and swap and trim the surrounding edits.
+          diffs.splice(pointer, 0, [
+            DIFF_EQUAL,
+            deletion.substring(0, overlap_length2),
+          ]);
+          diffs[pointer - 1][0] = DIFF_INSERT;
+          diffs[pointer - 1][1] = insertion.substring(
+            0,
+            insertion.length - overlap_length2
+          );
+          diffs[pointer + 1][0] = DIFF_DELETE;
+          diffs[pointer + 1][1] = deletion.substring(overlap_length2);
+          pointer++;
+        }
+      }
+      pointer++;
+    }
+    pointer++;
+  }
+}
+
+var nonAlphaNumericRegex_ = /[^a-zA-Z0-9]/;
+var whitespaceRegex_ = /\s/;
+var linebreakRegex_ = /[\r\n]/;
+var blanklineEndRegex_ = /\n\r?\n$/;
+var blanklineStartRegex_ = /^\r?\n\r?\n/;
+
+/**
+ * Look for single edits surrounded on both sides by equalities
+ * which can be shifted sideways to align the edit to a word boundary.
+ * e.g: The c<ins>at c</ins>ame. -> The <ins>cat </ins>came.
+ * @param {!Array.<!diff_match_patch.Diff>} diffs Array of diff tuples.
+ */
+function diff_cleanupSemanticLossless(diffs) {
+  /**
+   * Given two strings, compute a score representing whether the internal
+   * boundary falls on logical boundaries.
+   * Scores range from 6 (best) to 0 (worst).
+   * Closure, but does not reference any external variables.
+   * @param {string} one First string.
+   * @param {string} two Second string.
+   * @return {number} The score.
+   * @private
+   */
+  function diff_cleanupSemanticScore_(one, two) {
+    if (!one || !two) {
+      // Edges are the best.
+      return 6;
+    }
+
+    // Each port of this function behaves slightly differently due to
+    // subtle differences in each language's definition of things like
+    // 'whitespace'.  Since this function's purpose is largely cosmetic,
+    // the choice has been made to use each language's native features
+    // rather than force total conformity.
+    var char1 = one.charAt(one.length - 1);
+    var char2 = two.charAt(0);
+    var nonAlphaNumeric1 = char1.match(nonAlphaNumericRegex_);
+    var nonAlphaNumeric2 = char2.match(nonAlphaNumericRegex_);
+    var whitespace1 = nonAlphaNumeric1 && char1.match(whitespaceRegex_);
+    var whitespace2 = nonAlphaNumeric2 && char2.match(whitespaceRegex_);
+    var lineBreak1 = whitespace1 && char1.match(linebreakRegex_);
+    var lineBreak2 = whitespace2 && char2.match(linebreakRegex_);
+    var blankLine1 = lineBreak1 && one.match(blanklineEndRegex_);
+    var blankLine2 = lineBreak2 && two.match(blanklineStartRegex_);
+
+    if (blankLine1 || blankLine2) {
+      // Five points for blank lines.
+      return 5;
+    } else if (lineBreak1 || lineBreak2) {
+      // Four points for line breaks.
+      return 4;
+    } else if (nonAlphaNumeric1 && !whitespace1 && whitespace2) {
+      // Three points for end of sentences.
+      return 3;
+    } else if (whitespace1 || whitespace2) {
+      // Two points for whitespace.
+      return 2;
+    } else if (nonAlphaNumeric1 || nonAlphaNumeric2) {
+      // One point for non-alphanumeric.
+      return 1;
+    }
+    return 0;
+  }
+
+  var pointer = 1;
+  // Intentionally ignore the first and last element (don't need checking).
+  while (pointer < diffs.length - 1) {
+    if (
+      diffs[pointer - 1][0] == DIFF_EQUAL &&
+      diffs[pointer + 1][0] == DIFF_EQUAL
+    ) {
+      // This is a single edit surrounded by equalities.
+      var equality1 = diffs[pointer - 1][1];
+      var edit = diffs[pointer][1];
+      var equality2 = diffs[pointer + 1][1];
+
+      // First, shift the edit as far left as possible.
+      var commonOffset = diff_commonSuffix(equality1, edit);
+      if (commonOffset) {
+        var commonString = edit.substring(edit.length - commonOffset);
+        equality1 = equality1.substring(0, equality1.length - commonOffset);
+        edit = commonString + edit.substring(0, edit.length - commonOffset);
+        equality2 = commonString + equality2;
+      }
+
+      // Second, step character by character right, looking for the best fit.
+      var bestEquality1 = equality1;
+      var bestEdit = edit;
+      var bestEquality2 = equality2;
+      var bestScore =
+        diff_cleanupSemanticScore_(equality1, edit) +
+        diff_cleanupSemanticScore_(edit, equality2);
+      while (edit.charAt(0) === equality2.charAt(0)) {
+        equality1 += edit.charAt(0);
+        edit = edit.substring(1) + equality2.charAt(0);
+        equality2 = equality2.substring(1);
+        var score =
+          diff_cleanupSemanticScore_(equality1, edit) +
+          diff_cleanupSemanticScore_(edit, equality2);
+        // The >= encourages trailing rather than leading whitespace on edits.
+        if (score >= bestScore) {
+          bestScore = score;
+          bestEquality1 = equality1;
+          bestEdit = edit;
+          bestEquality2 = equality2;
+        }
+      }
+
+      if (diffs[pointer - 1][1] != bestEquality1) {
+        // We have an improvement, save it back to the diff.
+        if (bestEquality1) {
+          diffs[pointer - 1][1] = bestEquality1;
+        } else {
+          diffs.splice(pointer - 1, 1);
+          pointer--;
+        }
+        diffs[pointer][1] = bestEdit;
+        if (bestEquality2) {
+          diffs[pointer + 1][1] = bestEquality2;
+        } else {
+          diffs.splice(pointer + 1, 1);
+          pointer--;
+        }
+      }
+    }
+    pointer++;
+  }
+}
 
 /**
  * Reorder and merge like edit sections.  Merge equalities.
@@ -467,12 +797,12 @@ function diff_halfMatch_(text1, text2) {
  * @param {boolean} fix_unicode Whether to normalize to a unicode-correct diff
  */
 function diff_cleanupMerge(diffs, fix_unicode) {
-  diffs.push([DIFF_EQUAL, '']);  // Add a dummy entry at the end.
+  diffs.push([DIFF_EQUAL, ""]); // Add a dummy entry at the end.
   var pointer = 0;
   var count_delete = 0;
   var count_insert = 0;
-  var text_delete = '';
-  var text_insert = '';
+  var text_delete = "";
+  var text_insert = "";
   var commonlength;
   while (pointer < diffs.length) {
     if (pointer < diffs.length - 1 && !diffs[pointer][1]) {
@@ -481,7 +811,6 @@ function diff_cleanupMerge(diffs, fix_unicode) {
     }
     switch (diffs[pointer][0]) {
       case DIFF_INSERT:
-
         count_insert++;
         text_insert += diffs[pointer][1];
         pointer++;
@@ -504,9 +833,15 @@ function diff_cleanupMerge(diffs, fix_unicode) {
           // inserting 'AC', and then the common suffix 'AC' will be eliminated.  in this
           // particular case, both equalities go away, we absorb any previous inequalities,
           // and we keep scanning for the next equality before rewriting the tuples.
-          if (previous_equality >= 0 && ends_with_pair_start(diffs[previous_equality][1])) {
+          if (
+            previous_equality >= 0 &&
+            ends_with_pair_start(diffs[previous_equality][1])
+          ) {
             var stray = diffs[previous_equality][1].slice(-1);
-            diffs[previous_equality][1] = diffs[previous_equality][1].slice(0, -1);
+            diffs[previous_equality][1] = diffs[previous_equality][1].slice(
+              0,
+              -1
+            );
             text_delete = stray + text_delete;
             text_insert = stray + text_insert;
             if (!diffs[previous_equality][1]) {
@@ -546,9 +881,15 @@ function diff_cleanupMerge(diffs, fix_unicode) {
             commonlength = diff_commonPrefix(text_insert, text_delete);
             if (commonlength !== 0) {
               if (previous_equality >= 0) {
-                diffs[previous_equality][1] += text_insert.substring(0, commonlength);
+                diffs[previous_equality][1] += text_insert.substring(
+                  0,
+                  commonlength
+                );
               } else {
-                diffs.splice(0, 0, [DIFF_EQUAL, text_insert.substring(0, commonlength)]);
+                diffs.splice(0, 0, [
+                  DIFF_EQUAL,
+                  text_insert.substring(0, commonlength),
+                ]);
                 pointer++;
               }
               text_insert = text_insert.substring(commonlength);
@@ -558,9 +899,16 @@ function diff_cleanupMerge(diffs, fix_unicode) {
             commonlength = diff_commonSuffix(text_insert, text_delete);
             if (commonlength !== 0) {
               diffs[pointer][1] =
-                text_insert.substring(text_insert.length - commonlength) + diffs[pointer][1];
-              text_insert = text_insert.substring(0, text_insert.length - commonlength);
-              text_delete = text_delete.substring(0, text_delete.length - commonlength);
+                text_insert.substring(text_insert.length - commonlength) +
+                diffs[pointer][1];
+              text_insert = text_insert.substring(
+                0,
+                text_insert.length - commonlength
+              );
+              text_delete = text_delete.substring(
+                0,
+                text_delete.length - commonlength
+              );
             }
           }
           // Delete the offending records and add the merged ones.
@@ -575,7 +923,12 @@ function diff_cleanupMerge(diffs, fix_unicode) {
             diffs.splice(pointer - n, n, [DIFF_DELETE, text_delete]);
             pointer = pointer - n + 1;
           } else {
-            diffs.splice(pointer - n, n, [DIFF_DELETE, text_delete], [DIFF_INSERT, text_insert]);
+            diffs.splice(
+              pointer - n,
+              n,
+              [DIFF_DELETE, text_delete],
+              [DIFF_INSERT, text_insert]
+            );
             pointer = pointer - n + 2;
           }
         }
@@ -588,13 +941,13 @@ function diff_cleanupMerge(diffs, fix_unicode) {
         }
         count_insert = 0;
         count_delete = 0;
-        text_delete = '';
-        text_insert = '';
+        text_delete = "";
+        text_insert = "";
         break;
     }
   }
-  if (diffs[diffs.length - 1][1] === '') {
-    diffs.pop();  // Remove the dummy entry at the end.
+  if (diffs[diffs.length - 1][1] === "") {
+    diffs.pop(); // Remove the dummy entry at the end.
   }
 
   // Second pass: look for single edits surrounded on both sides by equalities
@@ -604,20 +957,30 @@ function diff_cleanupMerge(diffs, fix_unicode) {
   pointer = 1;
   // Intentionally ignore the first and last element (don't need checking).
   while (pointer < diffs.length - 1) {
-    if (diffs[pointer - 1][0] === DIFF_EQUAL &&
-      diffs[pointer + 1][0] === DIFF_EQUAL) {
+    if (
+      diffs[pointer - 1][0] === DIFF_EQUAL &&
+      diffs[pointer + 1][0] === DIFF_EQUAL
+    ) {
       // This is a single edit surrounded by equalities.
-      if (diffs[pointer][1].substring(diffs[pointer][1].length -
-        diffs[pointer - 1][1].length) === diffs[pointer - 1][1]) {
+      if (
+        diffs[pointer][1].substring(
+          diffs[pointer][1].length - diffs[pointer - 1][1].length
+        ) === diffs[pointer - 1][1]
+      ) {
         // Shift the edit over the previous equality.
-        diffs[pointer][1] = diffs[pointer - 1][1] +
-          diffs[pointer][1].substring(0, diffs[pointer][1].length -
-            diffs[pointer - 1][1].length);
+        diffs[pointer][1] =
+          diffs[pointer - 1][1] +
+          diffs[pointer][1].substring(
+            0,
+            diffs[pointer][1].length - diffs[pointer - 1][1].length
+          );
         diffs[pointer + 1][1] = diffs[pointer - 1][1] + diffs[pointer + 1][1];
         diffs.splice(pointer - 1, 1);
         changes = true;
-      } else if (diffs[pointer][1].substring(0, diffs[pointer + 1][1].length) ==
-        diffs[pointer + 1][1]) {
+      } else if (
+        diffs[pointer][1].substring(0, diffs[pointer + 1][1].length) ==
+        diffs[pointer + 1][1]
+      ) {
         // Shift the edit over the next equality.
         diffs[pointer - 1][1] += diffs[pointer + 1][1];
         diffs[pointer][1] =
@@ -633,14 +996,14 @@ function diff_cleanupMerge(diffs, fix_unicode) {
   if (changes) {
     diff_cleanupMerge(diffs, fix_unicode);
   }
-};
+}
 
 function is_surrogate_pair_start(charCode) {
-  return charCode >= 0xD800 && charCode <= 0xDBFF;
+  return charCode >= 0xd800 && charCode <= 0xdbff;
 }
 
 function is_surrogate_pair_end(charCode) {
-  return charCode >= 0xDC00 && charCode <= 0xDFFF;
+  return charCode >= 0xdc00 && charCode <= 0xdfff;
 }
 
 function starts_with_pair_end(str) {
@@ -669,16 +1032,17 @@ function make_edit_splice(before, oldMiddle, newMiddle, after) {
     [DIFF_EQUAL, before],
     [DIFF_DELETE, oldMiddle],
     [DIFF_INSERT, newMiddle],
-    [DIFF_EQUAL, after]
+    [DIFF_EQUAL, after],
   ]);
 }
 
 function find_cursor_edit_diff(oldText, newText, cursor_pos) {
   // note: this runs after equality check has ruled out exact equality
-  var oldRange = typeof cursor_pos === 'number' ?
-    { index: cursor_pos, length: 0 } : cursor_pos.oldRange;
-  var newRange = typeof cursor_pos === 'number' ?
-    null : cursor_pos.newRange;
+  var oldRange =
+    typeof cursor_pos === "number"
+      ? { index: cursor_pos, length: 0 }
+      : cursor_pos.oldRange;
+  var newRange = typeof cursor_pos === "number" ? null : cursor_pos.newRange;
   // take into account the old and new selection to generate the best diff
   // possible for a text edit.  for example, a text change from "xxx" to "xx"
   // could be a delete or forwards-delete of any one of the x's, or the
@@ -761,10 +1125,10 @@ function find_cursor_edit_diff(oldText, newText, cursor_pos) {
   return null;
 }
 
-function diff(text1, text2, cursor_pos) {
+function diff(text1, text2, cursor_pos, cleanup) {
   // only pass fix_unicode=true at the top level, not when diff_main is
   // recursively invoked
-  return diff_main(text1, text2, cursor_pos, true);
+  return diff_main(text1, text2, cursor_pos, cleanup, true);
 }
 
 diff.INSERT = DIFF_INSERT;