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+/**
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+ * Author: @jhchen - https://github.com/jhchen
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+ * Modified by: @lucascalion - 23/07/2019
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+ * This library modifies the diff-patch-match library by Neil Fraser
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+ * by removing the patch and match functionality and certain advanced
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+ * options in the diff function. The original license is as follows:
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+ *
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+ * ===
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+ *
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+ * Diff Match and Patch
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+ *
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+ * Copyright 2006 Google Inc.
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+ * http://code.google.com/p/google-diff-match-patch/
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+ *
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+ * Licensed under the Apache License, Version 2.0 (the "License");
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+ * you may not use this file except in compliance with the License.
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+ * You may obtain a copy of the License at
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+ *
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+ * http://www.apache.org/licenses/LICENSE-2.0
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+ *
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+ * Unless required by applicable law or agreed to in writing, software
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+ * distributed under the License is distributed on an "AS IS" BASIS,
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+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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+ * See the License for the specific language governing permissions and
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+ * limitations under the License.
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+ */
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+
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+
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+/**
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+ * The data structure representing a diff is an array of tuples:
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+ * [[DIFF_DELETE, 'Hello'], [DIFF_INSERT, 'Goodbye'], [DIFF_EQUAL, ' world.']]
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+ * which means: delete 'Hello', add 'Goodbye' and keep ' world.'
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+ */
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+const DIFF_DELETE = -1;
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+const DIFF_INSERT = 1;
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+const DIFF_EQUAL = 0;
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+
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+
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+/**
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+ * Find the differences between two texts. Simplifies the problem by stripping
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+ * any common prefix or suffix off the texts before diffing.
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+ * @param {string} text1 Old string to be diffed.
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+ * @param {string} text2 New string to be diffed.
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+ * @param {Int|Object} [cursor_pos] Edit position in text1 or object with more info
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+ * @return {Array} Array of diff tuples.
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+ */
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+function diff_main(text1, text2, cursor_pos, _fix_unicode) {
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+ // Check for equality
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+ if (text1 === text2) {
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+ if (text1) {
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+ return [[DIFF_EQUAL, text1]];
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+ }
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+ return [];
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+ }
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+
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+ if (cursor_pos != null) {
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+ const editdiff = find_cursor_edit_diff(text1, text2, cursor_pos);
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+ if (editdiff) {
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+ return editdiff;
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+ }
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+ }
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+
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+ // Trim off common prefix (speedup).
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+ let commonlength = diff_commonPrefix(text1, text2);
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+ const commonprefix = text1.substring(0, commonlength);
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+ text1 = text1.substring(commonlength);
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+ text2 = text2.substring(commonlength);
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+
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+ // Trim off common suffix (speedup).
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+ commonlength = diff_commonSuffix(text1, text2);
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+ const commonsuffix = text1.substring(text1.length - commonlength);
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+ text1 = text1.substring(0, text1.length - commonlength);
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+ text2 = text2.substring(0, text2.length - commonlength);
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+
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+ // Compute the diff on the middle block.
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+ const diffs = diff_compute_(text1, text2);
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+
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+ // Restore the prefix and suffix.
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+ if (commonprefix) {
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+ diffs.unshift([DIFF_EQUAL, commonprefix]);
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+ }
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+ if (commonsuffix) {
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+ diffs.push([DIFF_EQUAL, commonsuffix]);
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+ }
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+ diff_cleanupMerge(diffs, _fix_unicode);
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+ return diffs;
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+}
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+
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+
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+/**
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+ * Find the differences between two texts. Assumes that the texts do not
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+ * have any common prefix or suffix.
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+ * @param {string} text1 Old string to be diffed.
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+ * @param {string} text2 New string to be diffed.
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+ * @return {Array} Array of diff tuples.
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+ */
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+function diff_compute_(text1, text2) {
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+ let diffs;
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+
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+ if (!text1) {
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+ // Just add some text (speedup).
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+ return [[DIFF_INSERT, text2]];
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+ }
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+
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+ if (!text2) {
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+ // Just delete some text (speedup).
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+ return [[DIFF_DELETE, text1]];
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+ }
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+
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+ const longtext = text1.length > text2.length ? text1 : text2;
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+ const shorttext = text1.length > text2.length ? text2 : text1;
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+ const i = longtext.indexOf(shorttext);
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+ if (i !== -1) {
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+ // Shorter text is inside the longer text (speedup).
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+ diffs = [
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+ [DIFF_INSERT, longtext.substring(0, i)],
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+ [DIFF_EQUAL, shorttext],
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+ [DIFF_INSERT, longtext.substring(i + shorttext.length)]
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+ ];
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+ // Swap insertions for deletions if diff is reversed.
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+ if (text1.length > text2.length) {
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+ diffs[0][0] = diffs[2][0] = DIFF_DELETE;
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+ }
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+ return diffs;
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+ }
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+
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+ if (shorttext.length === 1) {
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+ // Single character string.
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+ // After the previous speedup, the character can't be an equality.
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+ return [[DIFF_DELETE, text1], [DIFF_INSERT, text2]];
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+ }
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+
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+ // Check to see if the problem can be split in two.
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+ var hm = diff_halfMatch_(text1, text2);
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+ if (hm) {
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+ // A half-match was found, sort out the return data.
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+ var text1_a = hm[0];
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+ var text1_b = hm[1];
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+ var text2_a = hm[2];
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+ var text2_b = hm[3];
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+ var mid_common = hm[4];
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+ // Send both pairs off for separate processing.
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+ var diffs_a = diff_main(text1_a, text2_a);
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+ var diffs_b = diff_main(text1_b, text2_b);
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+ // Merge the results.
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+ return diffs_a.concat([[DIFF_EQUAL, mid_common]], diffs_b);
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+ }
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+
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+ return diff_bisect_(text1, text2);
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+}
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+
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+
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+/**
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+ * Find the 'middle snake' of a diff, split the problem in two
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+ * and return the recursively constructed diff.
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+ * See Myers 1986 paper: An O(ND) Difference Algorithm and Its Variations.
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+ * @param {string} text1 Old string to be diffed.
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+ * @param {string} text2 New string to be diffed.
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+ * @return {Array} Array of diff tuples.
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+ * @private
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+ */
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+function diff_bisect_(text1, text2) {
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+ // Cache the text lengths to prevent multiple calls.
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+ const text1_length = text1.length;
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+ const text2_length = text2.length;
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+ const max_d = Math.ceil((text1_length + text2_length) / 2);
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+ const v_offset = max_d;
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+ const v_length = 2 * max_d;
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+ const v1 = new Array(v_length);
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+ const v2 = new Array(v_length);
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+ // Setting all elements to -1 is faster in Chrome & Firefox than mixing
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+ // integers and undefined.
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+ for (var x = 0; x < v_length; x++) {
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+ v1[x] = -1;
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+ v2[x] = -1;
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+ }
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+ v1[v_offset + 1] = 0;
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+ v2[v_offset + 1] = 0;
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+ const delta = text1_length - text2_length;
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+ // If the total number of characters is odd, then the front path will collide
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+ // with the reverse path.
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+ const front = (delta % 2 !== 0);
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+ // Offsets for start and end of k loop.
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+ // Prevents mapping of space beyond the grid.
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+ let k1start = 0;
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+ let k1end = 0;
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+ let k2start = 0;
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+ let k2end = 0;
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+ for (let d = 0; d < max_d; d++) {
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+ // Walk the front path one step.
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+ for (let k1 = -d + k1start; k1 <= d - k1end; k1 += 2) {
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+ const k1_offset = v_offset + k1;
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+ let x1;
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+ if (k1 === -d || (k1 !== d && v1[k1_offset - 1] < v1[k1_offset + 1])) {
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+ x1 = v1[k1_offset + 1];
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+ } else {
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+ x1 = v1[k1_offset - 1] + 1;
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+ }
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+ let y1 = x1 - k1;
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+ while (
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+ x1 < text1_length && y1 < text2_length &&
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+ text1.charAt(x1) === text2.charAt(y1)
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+ ) {
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+ x1++;
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+ y1++;
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+ }
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+ v1[k1_offset] = x1;
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+ if (x1 > text1_length) {
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+ // Ran off the right of the graph.
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+ k1end += 2;
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+ } else if (y1 > text2_length) {
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+ // Ran off the bottom of the graph.
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+ k1start += 2;
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+ } else if (front) {
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+ const k2_offset = v_offset + delta - k1;
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+ if (k2_offset >= 0 && k2_offset < v_length && v2[k2_offset] !== -1) {
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+ // Mirror x2 onto top-left coordinate system.
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+ const x2 = text1_length - v2[k2_offset];
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+ if (x1 >= x2) {
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+ // Overlap detfrontected.
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+ return diff_bisectSplit_(text1, text2, x1, y1);
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+ }
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+ }
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+ }
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+ }
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+
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+ // Walk the reverse path one step.
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+ for (let k2 = -d + k2start; k2 <= d - k2end; k2 += 2) {
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+ const k2_offset = v_offset + k2;
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+ let x2;
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+ if (k2 === -d || (k2 !== d && v2[k2_offset - 1] < v2[k2_offset + 1])) {
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+ x2 = v2[k2_offset + 1];
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+ } else {
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+ x2 = v2[k2_offset - 1] + 1;
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+ }
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+ let y2 = x2 - k2;
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+ while (
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+ x2 < text1_length && y2 < text2_length &&
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+ text1.charAt(text1_length - x2 - 1) === text2.charAt(text2_length - y2 - 1)
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+ ) {
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+ x2++;
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+ y2++;
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+ }
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+ v2[k2_offset] = x2;
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+ if (x2 > text1_length) {
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+ // Ran off the left of the graph.
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+ k2end += 2;
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+ } else if (y2 > text2_length) {
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+ // Ran off the top of the graph.
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+ k2start += 2;
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+ } else if (!front) {
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+ const k1_offset = v_offset + delta - k2;
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+ if (k1_offset >= 0 && k1_offset < v_length && v1[k1_offset] !== -1) {
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+ const x1 = v1[k1_offset];
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+ const y1 = v_offset + x1 - k1_offset;
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+ // Mirror x2 onto top-left coordinate system.
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+ x2 = text1_length - x2;
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+ if (x1 >= x2) {
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+ // Overlap detected.
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+ return diff_bisectSplit_(text1, text2, x1, y1);
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+ }
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+ }
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+ }
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+ }
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+ }
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+ // Diff took too long and hit the deadline or
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+ // number of diffs equals number of characters, no commonality at all.
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+ return [[DIFF_DELETE, text1], [DIFF_INSERT, text2]];
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+}
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+
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+
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+/**
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+ * Given the location of the 'middle snake', split the diff in two parts
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+ * and recurse.
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+ * @param {string} text1 Old string to be diffed.
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+ * @param {string} text2 New string to be diffed.
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+ * @param {number} x Index of split point in text1.
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+ * @param {number} y Index of split point in text2.
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+ * @return {Array} Array of diff tuples.
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+ */
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+function diff_bisectSplit_(text1, text2, x, y) {
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+ const text1a = text1.substring(0, x);
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+ const text2a = text2.substring(0, y);
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+ const text1b = text1.substring(x);
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+ const text2b = text2.substring(y);
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+
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+ // Compute both diffs serially.
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+ const diffs = diff_main(text1a, text2a);
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+ const diffsb = diff_main(text1b, text2b);
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+
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+ return diffs.concat(diffsb);
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+}
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+
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+
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+/**
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+ * Determine the common prefix of two strings.
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+ * @param {string} text1 First string.
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+ * @param {string} text2 Second string.
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+ * @return {number} The number of characters common to the start of each
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+ * string.
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+ */
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+function diff_commonPrefix(text1, text2) {
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+ // Quick check for common null cases.
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+ if (!text1 || !text2 || text1.charAt(0) !== text2.charAt(0)) {
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+ return 0;
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+ }
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+ // Binary search.
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+ // Performance analysis: http://neil.fraser.name/news/2007/10/09/
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+ let pointermin = 0;
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+ let pointermax = Math.min(text1.length, text2.length);
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+ let pointermid = pointermax;
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+ let pointerstart = 0;
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+ while (pointermin < pointermid) {
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+ if (
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+ text1.substring(pointerstart, pointermid) ==
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+ text2.substring(pointerstart, pointermid)
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+ ) {
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+ pointermin = pointermid;
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+ pointerstart = pointermin;
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+ } else {
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+ pointermax = pointermid;
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+ }
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+ pointermid = Math.floor((pointermax - pointermin) / 2 + pointermin);
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+ }
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+
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+ if (is_surrogate_pair_start(text1.charCodeAt(pointermid - 1))) {
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+ pointermid--;
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+ }
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+
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+ return pointermid;
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+}
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+
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+
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+/**
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+ * Determine the common suffix of two strings.
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+ * @param {string} text1 First string.
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+ * @param {string} text2 Second string.
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+ * @return {number} The number of characters common to the end of each string.
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+ */
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+function diff_commonSuffix(text1, text2) {
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+ // Quick check for common null cases.
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+ if (!text1 || !text2 || text1.slice(-1) !== text2.slice(-1)) {
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+ return 0;
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+ }
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+ // Binary search.
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+ // Performance analysis: http://neil.fraser.name/news/2007/10/09/
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+ let pointermin = 0;
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+ let pointermax = Math.min(text1.length, text2.length);
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+ let pointermid = pointermax;
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+ let pointerend = 0;
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+ while (pointermin < pointermid) {
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+ if (
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+ text1.substring(text1.length - pointermid, text1.length - pointerend) ==
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+ text2.substring(text2.length - pointermid, text2.length - pointerend)
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+ ) {
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+ pointermin = pointermid;
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+ pointerend = pointermin;
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+ } else {
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+ pointermax = pointermid;
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+ }
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+ pointermid = Math.floor((pointermax - pointermin) / 2 + pointermin);
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+ }
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+
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+ if (is_surrogate_pair_end(text1.charCodeAt(text1.length - pointermid))) {
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+ pointermid--;
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+ }
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+
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+ return pointermid;
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+}
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+
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+
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+/**
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+ * Do the two texts share a substring which is at least half the length of the
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+ * longer text?
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+ * This speedup can produce non-minimal diffs.
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+ * @param {string} text1 First string.
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+ * @param {string} text2 Second string.
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+ * @return {Array.<string>} Five element Array, containing the prefix of
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+ * text1, the suffix of text1, the prefix of text2, the suffix of
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+ * text2 and the common middle. Or null if there was no match.
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+ */
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+function diff_halfMatch_(text1, text2) {
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+ const longtext = text1.length > text2.length ? text1 : text2;
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+ const shorttext = text1.length > text2.length ? text2 : text1;
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+ if (longtext.length < 4 || shorttext.length * 2 < longtext.length) {
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+ return null; // Pointless.
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+ }
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+
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+ /**
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+ * Does a substring of shorttext exist within longtext such that the substring
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|
|
+ * is at least half the length of longtext?
|
|
|
+ * Closure, but does not reference any external variables.
|
|
|
+ * @param {string} longtext Longer string.
|
|
|
+ * @param {string} shorttext Shorter string.
|
|
|
+ * @param {number} i Start index of quarter length substring within longtext.
|
|
|
+ * @return {Array.<string>} Five element Array, containing the prefix of
|
|
|
+ * longtext, the suffix of longtext, the prefix of shorttext, the suffix
|
|
|
+ * of shorttext and the common middle. Or null if there was no match.
|
|
|
+ * @private
|
|
|
+ */
|
|
|
+ function diff_halfMatchI_(longtext, shorttext, i) {
|
|
|
+ // Start with a 1/4 length substring at position i as a seed.
|
|
|
+ const seed = longtext.substring(i, i + Math.floor(longtext.length / 4));
|
|
|
+ let j = -1;
|
|
|
+ let best_common = '';
|
|
|
+ let best_longtext_a, best_longtext_b, best_shorttext_a, best_shorttext_b;
|
|
|
+ while ((j = shorttext.indexOf(seed, j + 1)) !== -1) {
|
|
|
+ const prefixLength = diff_commonPrefix(
|
|
|
+ longtext.substring(i), shorttext.substring(j));
|
|
|
+ const suffixLength = diff_commonSuffix(
|
|
|
+ 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_longtext_a = longtext.substring(0, i - suffixLength);
|
|
|
+ best_longtext_b = longtext.substring(i + prefixLength);
|
|
|
+ best_shorttext_a = shorttext.substring(0, j - suffixLength);
|
|
|
+ best_shorttext_b = shorttext.substring(j + prefixLength);
|
|
|
+ }
|
|
|
+ }
|
|
|
+ if (best_common.length * 2 >= longtext.length) {
|
|
|
+ return [
|
|
|
+ best_longtext_a, best_longtext_b,
|
|
|
+ best_shorttext_a, best_shorttext_b, best_common
|
|
|
+ ];
|
|
|
+ } else {
|
|
|
+ return null;
|
|
|
+ }
|
|
|
+ }
|
|
|
+
|
|
|
+ // First check if the second quarter is the seed for a half-match.
|
|
|
+ const hm1 = diff_halfMatchI_(longtext, shorttext, Math.ceil(longtext.length / 4));
|
|
|
+ // Check again based on the third quarter.
|
|
|
+ const hm2 = diff_halfMatchI_(longtext, shorttext, Math.ceil(longtext.length / 2));
|
|
|
+ let hm;
|
|
|
+ if (!hm1 && !hm2) {
|
|
|
+ return null;
|
|
|
+ } else if (!hm2) {
|
|
|
+ hm = hm1;
|
|
|
+ } else if (!hm1) {
|
|
|
+ hm = hm2;
|
|
|
+ } else {
|
|
|
+ // Both matched. Select the longest.
|
|
|
+ hm = hm1[4].length > hm2[4].length ? hm1 : hm2;
|
|
|
+ }
|
|
|
+
|
|
|
+ // A half-match was found, sort out the return data.
|
|
|
+ let text1_a, text1_b, text2_a, text2_b;
|
|
|
+ if (text1.length > text2.length) {
|
|
|
+ text1_a = hm[0];
|
|
|
+ text1_b = hm[1];
|
|
|
+ text2_a = hm[2];
|
|
|
+ text2_b = hm[3];
|
|
|
+ } else {
|
|
|
+ text2_a = hm[0];
|
|
|
+ text2_b = hm[1];
|
|
|
+ text1_a = hm[2];
|
|
|
+ text1_b = hm[3];
|
|
|
+ }
|
|
|
+ const mid_common = hm[4];
|
|
|
+ return [text1_a, text1_b, text2_a, text2_b, mid_common];
|
|
|
+}
|
|
|
+
|
|
|
+
|
|
|
+/**
|
|
|
+ * Reorder and merge like edit sections. Merge equalities.
|
|
|
+ * Any edit section can move as long as it doesn't cross an equality.
|
|
|
+ * @param {Array} diffs Array of diff tuples.
|
|
|
+ * @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.
|
|
|
+ let pointer = 0;
|
|
|
+ let count_delete = 0;
|
|
|
+ let count_insert = 0;
|
|
|
+ let text_delete = '';
|
|
|
+ let text_insert = '';
|
|
|
+ let commonlength;
|
|
|
+ let previous_equality;
|
|
|
+ while (pointer < diffs.length) {
|
|
|
+ if (pointer < diffs.length - 1 && !diffs[pointer][1]) {
|
|
|
+ diffs.splice(pointer, 1);
|
|
|
+ continue;
|
|
|
+ }
|
|
|
+ switch (diffs[pointer][0]) {
|
|
|
+ case DIFF_INSERT:
|
|
|
+ count_insert++;
|
|
|
+ text_insert += diffs[pointer][1];
|
|
|
+ pointer++;
|
|
|
+ break;
|
|
|
+ case DIFF_DELETE:
|
|
|
+ count_delete++;
|
|
|
+ text_delete += diffs[pointer][1];
|
|
|
+ pointer++;
|
|
|
+ break;
|
|
|
+ case DIFF_EQUAL:
|
|
|
+ previous_equality = pointer - count_insert - count_delete - 1;
|
|
|
+ if (fix_unicode) {
|
|
|
+ // prevent splitting of unicode surrogate pairs. when fix_unicode is true,
|
|
|
+ // we assume that the old and new text in the diff are complete and correct
|
|
|
+ // unicode-encoded JS strings, but the tuple boundaries may fall between
|
|
|
+ // surrogate pairs. we fix this by shaving off stray surrogates from the end
|
|
|
+ // of the previous equality and the beginning of this equality. this may create
|
|
|
+ // empty equalities or a common prefix or suffix. for example, if AB and AC are
|
|
|
+ // emojis, `[[0, 'A'], [-1, 'BA'], [0, 'C']]` would turn into deleting 'ABAC' and
|
|
|
+ // 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])) {
|
|
|
+ const stray = diffs[previous_equality][1].slice(-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]) {
|
|
|
+ // emptied out previous equality, so delete it and include previous delete/insert
|
|
|
+ diffs.splice(previous_equality, 1);
|
|
|
+ pointer--;
|
|
|
+ var k = previous_equality - 1;
|
|
|
+ if (diffs[k] && diffs[k][0] === DIFF_INSERT) {
|
|
|
+ count_insert++;
|
|
|
+ text_insert = diffs[k][1] + text_insert;
|
|
|
+ k--;
|
|
|
+ }
|
|
|
+ if (diffs[k] && diffs[k][0] === DIFF_DELETE) {
|
|
|
+ count_delete++;
|
|
|
+ text_delete = diffs[k][1] + text_delete;
|
|
|
+ k--;
|
|
|
+ }
|
|
|
+ previous_equality = k;
|
|
|
+ }
|
|
|
+ }
|
|
|
+ if (starts_with_pair_end(diffs[pointer][1])) {
|
|
|
+ const stray = diffs[pointer][1].charAt(0);
|
|
|
+ diffs[pointer][1] = diffs[pointer][1].slice(1);
|
|
|
+ text_delete += stray;
|
|
|
+ text_insert += stray;
|
|
|
+ }
|
|
|
+ }
|
|
|
+ if (pointer < diffs.length - 1 && !diffs[pointer][1]) {
|
|
|
+ // for empty equality not at end, wait for next equality
|
|
|
+ diffs.splice(pointer, 1);
|
|
|
+ break;
|
|
|
+ }
|
|
|
+ if (text_delete.length > 0 || text_insert.length > 0) {
|
|
|
+ // note that diff_commonPrefix and diff_commonSuffix are unicode-aware
|
|
|
+ if (text_delete.length > 0 && text_insert.length > 0) {
|
|
|
+ // Factor out any common prefixes.
|
|
|
+ commonlength = diff_commonPrefix(text_insert, text_delete);
|
|
|
+ if (commonlength !== 0) {
|
|
|
+ if (previous_equality >= 0) {
|
|
|
+ diffs[previous_equality][1] += text_insert.substring(0, commonlength);
|
|
|
+ } else {
|
|
|
+ diffs.splice(0, 0, [DIFF_EQUAL, text_insert.substring(0, commonlength)]);
|
|
|
+ pointer++;
|
|
|
+ }
|
|
|
+ text_insert = text_insert.substring(commonlength);
|
|
|
+ text_delete = text_delete.substring(commonlength);
|
|
|
+ }
|
|
|
+ // Factor out any common suffixes.
|
|
|
+ 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);
|
|
|
+ }
|
|
|
+ }
|
|
|
+ // Delete the offending records and add the merged ones.
|
|
|
+ const n = count_insert + count_delete;
|
|
|
+ if (text_delete.length === 0 && text_insert.length === 0) {
|
|
|
+ diffs.splice(pointer - n, n);
|
|
|
+ pointer = pointer - n;
|
|
|
+ } else if (text_delete.length === 0) {
|
|
|
+ diffs.splice(pointer - n, n, [DIFF_INSERT, text_insert]);
|
|
|
+ pointer = pointer - n + 1;
|
|
|
+ } else if (text_insert.length === 0) {
|
|
|
+ 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]);
|
|
|
+ pointer = pointer - n + 2;
|
|
|
+ }
|
|
|
+ }
|
|
|
+ if (pointer !== 0 && diffs[pointer - 1][0] === DIFF_EQUAL) {
|
|
|
+ // Merge this equality with the previous one.
|
|
|
+ diffs[pointer - 1][1] += diffs[pointer][1];
|
|
|
+ diffs.splice(pointer, 1);
|
|
|
+ } else {
|
|
|
+ pointer++;
|
|
|
+ }
|
|
|
+ count_insert = 0;
|
|
|
+ count_delete = 0;
|
|
|
+ text_delete = '';
|
|
|
+ text_insert = '';
|
|
|
+ break;
|
|
|
+ }
|
|
|
+ }
|
|
|
+ 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
|
|
|
+ // which can be shifted sideways to eliminate an equality.
|
|
|
+ // e.g: A<ins>BA</ins>C -> <ins>AB</ins>AC
|
|
|
+ let changes = false;
|
|
|
+ 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.
|
|
|
+ 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][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]) {
|
|
|
+ // Shift the edit over the next equality.
|
|
|
+ diffs[pointer - 1][1] += diffs[pointer + 1][1];
|
|
|
+ diffs[pointer][1] =
|
|
|
+ diffs[pointer][1].substring(diffs[pointer + 1][1].length) +
|
|
|
+ diffs[pointer + 1][1];
|
|
|
+ diffs.splice(pointer + 1, 1);
|
|
|
+ changes = true;
|
|
|
+ }
|
|
|
+ }
|
|
|
+ pointer++;
|
|
|
+ }
|
|
|
+ // If shifts were made, the diff needs reordering and another shift sweep.
|
|
|
+ if (changes) {
|
|
|
+ diff_cleanupMerge(diffs, fix_unicode);
|
|
|
+ }
|
|
|
+}
|
|
|
+
|
|
|
+function is_surrogate_pair_start(charCode) {
|
|
|
+ return charCode >= 0xD800 && charCode <= 0xDBFF;
|
|
|
+}
|
|
|
+
|
|
|
+function is_surrogate_pair_end(charCode) {
|
|
|
+ return charCode >= 0xDC00 && charCode <= 0xDFFF;
|
|
|
+}
|
|
|
+
|
|
|
+function starts_with_pair_end(str) {
|
|
|
+ return is_surrogate_pair_end(str.charCodeAt(0));
|
|
|
+}
|
|
|
+
|
|
|
+function ends_with_pair_start(str) {
|
|
|
+ return is_surrogate_pair_start(str.charCodeAt(str.length - 1));
|
|
|
+}
|
|
|
+
|
|
|
+function remove_empty_tuples(tuples) {
|
|
|
+ const ret = [];
|
|
|
+ for (let i = 0; i < tuples.length; i++) {
|
|
|
+ if (tuples[i][1].length > 0) {
|
|
|
+ ret.push(tuples[i]);
|
|
|
+ }
|
|
|
+ }
|
|
|
+ return ret;
|
|
|
+}
|
|
|
+
|
|
|
+function make_edit_splice(before, oldMiddle, newMiddle, after) {
|
|
|
+ if (ends_with_pair_start(before) || starts_with_pair_end(after)) {
|
|
|
+ return null;
|
|
|
+ }
|
|
|
+ return remove_empty_tuples([
|
|
|
+ [DIFF_EQUAL, before],
|
|
|
+ [DIFF_DELETE, oldMiddle],
|
|
|
+ [DIFF_INSERT, newMiddle],
|
|
|
+ [DIFF_EQUAL, after]
|
|
|
+ ]);
|
|
|
+}
|
|
|
+
|
|
|
+function find_cursor_edit_diff(oldText, newText, cursor_pos) {
|
|
|
+ // note: this runs after equality check has ruled out exact equality
|
|
|
+ const oldRange = typeof cursor_pos === 'number' ?
|
|
|
+ { index: cursor_pos, length: 0 } : cursor_pos.oldRange;
|
|
|
+ const 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
|
|
|
+ // result of selecting two of the x's and typing "x".
|
|
|
+ const oldLength = oldText.length;
|
|
|
+ const newLength = newText.length;
|
|
|
+ if (oldRange.length === 0 && (newRange === null || newRange.length === 0)) {
|
|
|
+ // see if we have an insert or delete before or after cursor
|
|
|
+ const oldCursor = oldRange.index;
|
|
|
+ const oldBefore = oldText.slice(0, oldCursor);
|
|
|
+ const oldAfter = oldText.slice(oldCursor);
|
|
|
+ const maybeNewCursor = newRange ? newRange.index : null;
|
|
|
+ editBefore: {
|
|
|
+ // is this an insert or delete right before oldCursor?
|
|
|
+ const newCursor = oldCursor + newLength - oldLength;
|
|
|
+ if (maybeNewCursor !== null && maybeNewCursor !== newCursor) {
|
|
|
+ break editBefore;
|
|
|
+ }
|
|
|
+ if (newCursor < 0 || newCursor > newLength) {
|
|
|
+ break editBefore;
|
|
|
+ }
|
|
|
+ const newBefore = newText.slice(0, newCursor);
|
|
|
+ const newAfter = newText.slice(newCursor);
|
|
|
+ if (newAfter !== oldAfter) {
|
|
|
+ break editBefore;
|
|
|
+ }
|
|
|
+ const prefixLength = Math.min(oldCursor, newCursor);
|
|
|
+ const oldPrefix = oldBefore.slice(0, prefixLength);
|
|
|
+ const newPrefix = newBefore.slice(0, prefixLength);
|
|
|
+ if (oldPrefix !== newPrefix) {
|
|
|
+ break editBefore;
|
|
|
+ }
|
|
|
+ const oldMiddle = oldBefore.slice(prefixLength);
|
|
|
+ const newMiddle = newBefore.slice(prefixLength);
|
|
|
+ return make_edit_splice(oldPrefix, oldMiddle, newMiddle, oldAfter);
|
|
|
+ }
|
|
|
+ editAfter: {
|
|
|
+ // is this an insert or delete right after oldCursor?
|
|
|
+ if (maybeNewCursor !== null && maybeNewCursor !== oldCursor) {
|
|
|
+ break editAfter;
|
|
|
+ }
|
|
|
+ const cursor = oldCursor;
|
|
|
+ const newBefore = newText.slice(0, cursor);
|
|
|
+ const newAfter = newText.slice(cursor);
|
|
|
+ if (newBefore !== oldBefore) {
|
|
|
+ break editAfter;
|
|
|
+ }
|
|
|
+ const suffixLength = Math.min(oldLength - cursor, newLength - cursor);
|
|
|
+ const oldSuffix = oldAfter.slice(oldAfter.length - suffixLength);
|
|
|
+ const newSuffix = newAfter.slice(newAfter.length - suffixLength);
|
|
|
+ if (oldSuffix !== newSuffix) {
|
|
|
+ break editAfter;
|
|
|
+ }
|
|
|
+ const oldMiddle = oldAfter.slice(0, oldAfter.length - suffixLength);
|
|
|
+ const newMiddle = newAfter.slice(0, newAfter.length - suffixLength);
|
|
|
+ return make_edit_splice(oldBefore, oldMiddle, newMiddle, oldSuffix);
|
|
|
+ }
|
|
|
+ }
|
|
|
+ if (oldRange.length > 0 && newRange && newRange.length === 0) {
|
|
|
+ replaceRange: {
|
|
|
+ // see if diff could be a splice of the old selection range
|
|
|
+ const oldPrefix = oldText.slice(0, oldRange.index);
|
|
|
+ const oldSuffix = oldText.slice(oldRange.index + oldRange.length);
|
|
|
+ const prefixLength = oldPrefix.length;
|
|
|
+ const suffixLength = oldSuffix.length;
|
|
|
+ if (newLength < prefixLength + suffixLength) {
|
|
|
+ break replaceRange;
|
|
|
+ }
|
|
|
+ const newPrefix = newText.slice(0, prefixLength);
|
|
|
+ const newSuffix = newText.slice(newLength - suffixLength);
|
|
|
+ if (oldPrefix !== newPrefix || oldSuffix !== newSuffix) {
|
|
|
+ break replaceRange;
|
|
|
+ }
|
|
|
+ const oldMiddle = oldText.slice(prefixLength, oldLength - suffixLength);
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+ const newMiddle = newText.slice(prefixLength, newLength - suffixLength);
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+ return make_edit_splice(oldPrefix, oldMiddle, newMiddle, oldSuffix);
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+ }
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+ }
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+
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+ return null;
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+}
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+
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+function diff(text1, text2, cursor_pos) {
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+ // only pass fix_unicode=true at the top level, not when diff_main is
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+ // recursively invoked
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+ return diff_main(text1, text2, cursor_pos, true);
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+}
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+
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+diff.INSERT = DIFF_INSERT;
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+diff.DELETE = DIFF_DELETE;
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+diff.EQUAL = DIFF_EQUAL;
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+
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+export default diff;
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Lucas de Souza