Migrate diff-match-patch to a modern fork (#9511)

* Migrate to diff-match-patch-es & update api

* Update acknowledgements

* Update change notes

* Fix editcost attribute not working

* Make library compatible with ES2017

Author: Leilei332

core/acknowledgements.tid

@@ -5,3 +5,4 @@ TiddlyWiki incorporates code from these fine OpenSource projects:
 * [[The Stanford Javascript Crypto Library|http://bitwiseshiftleft.github.io/sjcl/]]
 * [[The Jasmine JavaScript Test Framework|https://jasmine.github.io/]]
 * [[modern-normalize by Sindre Sorhus|https://github.com/sindresorhus/modern-normalize]]
+* [[diff-match-patch-es by antfu|https://github.com/antfu/diff-match-patch-es]]

core/modules/filters/strings.js

@@ -71,107 +71,103 @@ exports.join = makeStringReducingOperator(
 	},null
 );
 
-var dmp = require("$:/core/modules/utils/diff-match-patch/diff_match_patch.js");
+const dmp = require("$:/core/modules/utils/diff-match-patch/diff_match_patch.js");
 
 exports.levenshtein = makeStringBinaryOperator(
 	function(a,b) {
-		var dmpObject = new dmp.diff_match_patch(),
-			diffs = dmpObject.diff_main(a,b);
-		return [dmpObject.diff_levenshtein(diffs) + ""];
+		const diffs = dmp.diffMain(a,b);
+		return [dmp.diffLevenshtein(diffs).toString()];
 	}
 );
 
 // these two functions are adapted from https://github.com/google/diff-match-patch/wiki/Line-or-Word-Diffs
 function diffLineWordMode(text1,text2,mode) {
-	var dmpObject = new dmp.diff_match_patch();
 	var a = diffPartsToChars(text1,text2,mode);
 	var lineText1 = a.chars1;
 	var lineText2 = a.chars2;
 	var lineArray = a.lineArray;
-	var diffs = dmpObject.diff_main(lineText1,lineText2,false);
-	dmpObject.diff_charsToLines_(diffs,lineArray);
+	var diffs = dmp.diffMain(lineText1,lineText2,false);
+	dmp.diffCharsToLines(diffs,lineArray);
 	return diffs;
 }
 
 function diffPartsToChars(text1,text2,mode) {
 	var lineArray = [];
 	var lineHash = {};
-	lineArray[0] = '';
+	lineArray[0] = "";
 
-    function diff_linesToPartsMunge_(text,mode) {
-        var chars = '';
-        var lineStart = 0;
-        var lineEnd = -1;
-        var lineArrayLength = lineArray.length,
-            regexpResult;
-        var searchRegexp = /\W+/g;
-        while(lineEnd < text.length - 1) {
-	        if(mode === "words") {
-                regexpResult = searchRegexp.exec(text);
-                lineEnd = searchRegexp.lastIndex;
-                if(regexpResult === null) {
-                lineEnd = text.length;
-                }
-                lineEnd = --lineEnd;
-            } else {
-                lineEnd = text.indexOf('\n', lineStart);
-                if(lineEnd == -1) {
-                    lineEnd = text.length - 1;
-                }
-            }
-            var line = text.substring(lineStart, lineEnd + 1);
+	function diff_linesToPartsMunge_(text,mode) {
+		var chars = "";
+		var lineStart = 0;
+		var lineEnd = -1;
+		var lineArrayLength = lineArray.length,
+			regexpResult;
+		var searchRegexp = /\W+/g;
+		while(lineEnd < text.length - 1) {
+			if(mode === "words") {
+				regexpResult = searchRegexp.exec(text);
+				lineEnd = searchRegexp.lastIndex;
+				if(regexpResult === null) {
+					lineEnd = text.length;
+				}
+				lineEnd = --lineEnd;
+			} else {
+				lineEnd = text.indexOf("\n", lineStart);
+				if(lineEnd == -1) {
+					lineEnd = text.length - 1;
+				}
+			}
+			var line = text.substring(lineStart, lineEnd + 1);
 
-            if(lineHash.hasOwnProperty ? lineHash.hasOwnProperty(line) : (lineHash[line] !== undefined)) {
+			if(lineHash.hasOwnProperty ? lineHash.hasOwnProperty(line) : (lineHash[line] !== undefined)) {
 				chars += String.fromCharCode(lineHash[line]);
-            } else {
-                if(lineArrayLength == maxLines) {
-                  line = text.substring(lineStart);
-                  lineEnd = text.length;
-                }
-                chars += String.fromCharCode(lineArrayLength);
-                lineHash[line] = lineArrayLength;
-                lineArray[lineArrayLength++] = line;
-            }
-            lineStart = lineEnd + 1;
-        }
-        return chars;
-    }
-    var maxLines = 40000;
-    var chars1 = diff_linesToPartsMunge_(text1,mode);
-    maxLines = 65535;
-    var chars2 = diff_linesToPartsMunge_(text2,mode);
-    return {chars1: chars1, chars2: chars2, lineArray: lineArray};
+			} else {
+				if(lineArrayLength == maxLines) {
+					line = text.substring(lineStart);
+					lineEnd = text.length;
+				}
+				chars += String.fromCharCode(lineArrayLength);
+				lineHash[line] = lineArrayLength;
+				lineArray[lineArrayLength++] = line;
+			}
+			lineStart = lineEnd + 1;
+		}
+		return chars;
+	}
+	var maxLines = 40000;
+	var chars1 = diff_linesToPartsMunge_(text1,mode);
+	maxLines = 65535;
+	var chars2 = diff_linesToPartsMunge_(text2,mode);
+	return {chars1: chars1, chars2: chars2, lineArray: lineArray};
 };
 
 exports.makepatches = function(source,operator,options) {
-	var dmpObject = new dmp.diff_match_patch(),
-		suffix = operator.suffix || "",
+	var suffix = operator.suffix || "",
 		result = [];
 
-		source(function(tiddler,title) {
-			var diffs, patches;
-			if(suffix === "lines" || suffix === "words") {
-				diffs = diffLineWordMode(title,operator.operand,suffix);
-				patches = dmpObject.patch_make(title,diffs);
-			} else {
-				patches = dmpObject.patch_make(title,operator.operand);
-			}
-			Array.prototype.push.apply(result,[dmpObject.patch_toText(patches)]);
-		});
+	source(function(tiddler,title) {
+		let diffs, patches;
+		if(suffix === "lines" || suffix === "words") {
+			diffs = diffLineWordMode(title,operator.operand,suffix);
+			patches = dmp.patchMake(title,diffs);
+		} else {
+			patches = dmp.patchMake(title,operator.operand);
+		}
+		Array.prototype.push.apply(result,[dmp.patchToText(patches)]);
+	});
 
 	return result;
 };
 
 exports.applypatches = makeStringBinaryOperator(
 	function(a,b) {
-		var dmpObject = new dmp.diff_match_patch(),
-			patches;
+		let patches;
 		try {
-			patches = dmpObject.patch_fromText(b);
+			patches = dmp.patchFromText(b);
 		} catch(e) {
 		}
 		if(patches) {
-			return [dmpObject.patch_apply(patches,a)[0]];
+			return [dmp.patchApply(patches,a)[0]];
 		} else {
 			return [a];
 		}