chore: make diff-match-patch optional

Author: nikku

lib/filters/texts.js

@@ -1,30 +1,26 @@
-/* global diff_match_patch */
-import dmp from 'diff-match-patch';
-
 let TEXT_DIFF = 2;
 let DEFAULT_MIN_LENGTH = 60;
 let cachedDiffPatch = null;
 
-let getDiffMatchPatch = function(required) {
+let getDiffMatchPatch = function(options = {}, required) {
+
   /* jshint camelcase: false */
 
   if (!cachedDiffPatch) {
     let instance;
-    /* eslint-disable camelcase, new-cap */
-    if (typeof diff_match_patch !== 'undefined') {
-
-      // already loaded, probably a browser
-      instance =
-        typeof diff_match_patch === 'function'
-          ? new diff_match_patch()
-          : new diff_match_patch.diff_match_patch();
-    } else if (dmp) {
-      try {
-        instance = dmp && new dmp();
-      } catch (err) {
-        instance = null;
-      }
+
+    const {
+      textDiff: {
+        diffMatchPatch
+      } = {}
+    } = options;
+
+    try {
+      instance = diffMatchPatch && new diffMatchPatch();
+    } catch (err) {
+      instance = null;
     }
+
     /* eslint-enable camelcase, new-cap */
     if (!instance) {
       if (!required) {
@@ -72,7 +68,7 @@ export const diffFilter = function textsDiffFilter(context) {
   }
 
   // large text, try to use a text-diff algorithm
-  let diffMatchPatch = getDiffMatchPatch();
+  let diffMatchPatch = getDiffMatchPatch(context.options);
   if (!diffMatchPatch) {
 
     // diff-match-patch library not available,
@@ -94,7 +90,7 @@ export const patchFilter = function textsPatchFilter(context) {
   }
 
   // text-diff, use a text-patch algorithm
-  const patch = getDiffMatchPatch(true).patch;
+  const patch = getDiffMatchPatch(context.options, true).patch;
   context.setResult(patch(context.left, context.delta[0])).exit();
 };
 patchFilter.filterName = 'texts';

lib/index.d.ts

@@ -21,7 +21,9 @@ export interface Config {
     };
     textDiff?: {
         // default 60, minimum string length (left and right sides) to use text diff algorythm: google-diff-match-patch
-        minLength: number,
+        minLength?: number,
+        // a diff-match-patch constructor for text diffing
+        diffMatchPatch?: any
     };
     /*
         this optional function can be specified to ignore object properties (eg. volatile data)

package-lock.json

@@ -30,11 +30,11 @@
     "patch"
   ],
   "dependencies": {
-    "diff-match-patch": "^1.0.0",
     "picocolors": "^1.0.1"
   },
   "devDependencies": {
     "chai": "^5.1.1",
+    "diff-match-patch": "^1.0.5",
     "eslint": "^8.57.0",
     "eslint-plugin-bpmn-io": "^1.0.1",
     "eslint-plugin-import": "^2.8.0",

package.json

@@ -1,3 +1,5 @@
+import DiffMatchPatch from 'diff-match-patch';
+
 const examples = {};
 
 const exampleDate = () => new Date(2020, 10, 30, 15, 10, 3);
@@ -570,6 +572,7 @@ examples.text = [
     right: largeText,
     delta: [ shortText, largeText ],
     reverse: [ largeText, shortText ],
+    options: { textDiff: { diffMatchPatch: DiffMatchPatch } },
   },
   {
     left: largeText,
@@ -589,24 +592,27 @@ examples.text = [
       2,
     ],
     exactReverse: false,
+    options: { textDiff: { diffMatchPatch: DiffMatchPatch } },
   },
   {
     name: 'larger than min length',
     options: {
       textDiff: {
+        diffMatchPatch: DiffMatchPatch,
         minLength: 10,
       },
     },
     left: largeText.substr(0, 10),
     right: largeText.substr(0, 11).replace(/Madre/g, 'Padre'),
     delta: [ '@@ -1,10 +1,11 @@\n -\n-M\n+P\n adre,%0Acu\n+a\n', 0, 2 ],
     reverse: [ '@@ -1,11 +1,10 @@\n -\n-P\n+M\n adre,%0Acu\n-a\n', 0, 2 ],
-    exactReverse: false,
+    exactReverse: false
   },
   {
     name: 'shorter than min length',
     options: {
       textDiff: {
+        diffMatchPatch: DiffMatchPatch,
         minLength: 10,
       },
     },