Merge pull request kpdecker#146 from wvanderdeijl/array

JsDiff.diffArrays to compare arrays

Author: kpdecker

README.md

@@ -55,6 +55,10 @@ or
 
     Returns a list of change objects (See below).
 
+* `JsDiff.diffArrays(oldArr, newArr[, options])` - diffs two arrays, comparing each item for strict equality (===).
+
+    Returns a list of change objects (See below).
+
 * `JsDiff.createTwoFilesPatch(oldFileName, newFileName, oldStr, newStr, oldHeader, newHeader)` - creates a unified diff patch.
 
     Parameters:

src/diff/array.js

@@ -0,0 +1,8 @@
+import Diff from './base';
+
+export const arrayDiff = new Diff();
+arrayDiff.tokenize = arrayDiff.join = function(value) {
+  return value.slice();
+};
+
+export function diffArrays(oldArr, newArr, callback) { return arrayDiff.diff(oldArr, newArr, callback); }

src/diff/base.js

@@ -36,7 +36,7 @@ Diff.prototype = {
     let oldPos = this.extractCommon(bestPath[0], newString, oldString, 0);
     if (bestPath[0].newPos + 1 >= newLen && oldPos + 1 >= oldLen) {
       // Identity per the equality and tokenizer
-      return done([{value: newString.join(''), count: newString.length}]);
+      return done([{value: this.join(newString), count: newString.length}]);
     }
 
     // Main worker method. checks all permutations of a given edit length for acceptance.
@@ -160,6 +160,9 @@ Diff.prototype = {
   },
   tokenize(value) {
     return value.split('');
+  },
+  join(chars) {
+    return chars.join('');
   }
 };
 
@@ -179,9 +182,9 @@ function buildValues(diff, components, newString, oldString, useLongestToken) {
           return oldValue.length > value.length ? oldValue : value;
         });
 
-        component.value = value.join('');
+        component.value = diff.join(value);
       } else {
-        component.value = newString.slice(newPos, newPos + component.count).join('');
+        component.value = diff.join(newString.slice(newPos, newPos + component.count));
       }
       newPos += component.count;
 
@@ -190,7 +193,7 @@ function buildValues(diff, components, newString, oldString, useLongestToken) {
         oldPos += component.count;
       }
     } else {
-      component.value = oldString.slice(oldPos, oldPos + component.count).join('');
+      component.value = diff.join(oldString.slice(oldPos, oldPos + component.count));
       oldPos += component.count;
 
       // Reverse add and remove so removes are output first to match common convention

src/index.js

@@ -23,6 +23,8 @@ import {diffSentences} from './diff/sentence';
 import {diffCss} from './diff/css';
 import {diffJson, canonicalize} from './diff/json';
 
+import {diffArrays} from './diff/array';
+
 import {applyPatch, applyPatches} from './patch/apply';
 import {parsePatch} from './patch/parse';
 import {structuredPatch, createTwoFilesPatch, createPatch} from './patch/create';
@@ -43,6 +45,8 @@ export {
   diffCss,
   diffJson,
 
+  diffArrays,
+
   structuredPatch,
   createTwoFilesPatch,
   createPatch,

test/diff/array.js

@@ -0,0 +1,19 @@
+import {diffArrays} from '../../lib/diff/array';
+
+import {expect} from 'chai';
+
+describe('diff/array', function() {
+  describe('#diffArrays', function() {
+    it('Should diff arrays', function() {
+      const a = {a: 0}, b = {b: 1}, c = {c: 2};
+      const diffResult = diffArrays([a, b, c], [a, c, b]);
+      console.log(diffResult);
+      expect(diffResult).to.deep.equals([
+          {count: 1, value: [a]},
+          {count: 1, value: [c], removed: undefined, added: true},
+          {count: 1, value: [b]},
+          {count: 1, value: [c], removed: true, added: undefined}
+      ]);
+    });
+  });
+});

test/index.js

@@ -16,6 +16,8 @@ describe('root exports', function() {
     expect(Diff.diffCss).to.exist;
     expect(Diff.diffJson).to.exist;
 
+    expect(Diff.diffArrays).to.exist;
+
     expect(Diff.structuredPatch).to.exist;
     expect(Diff.createTwoFilesPatch).to.exist;
     expect(Diff.createPatch).to.exist;