jsdiff-es

日本語のREADMEはこちらです: README.ja.md

A JavaScript text differencing library. Based on the algorithm proposed in "An O(ND) Difference Algorithm and its Variations" (Myers, 1986).

This is an ES module-focused implementation.

• Text Diffs: Compares text by character, word, line, or sentence.
• Specialized Diffs: Includes dedicated methods for comparing CSS, JSON objects, and arrays.
• Patching: Create and apply patches in the unified diff format.
• Flexible Options: Supports case-insensitivity, custom comparators, and whitespace handling.
• Environment Support: Works in Node.js, Deno, and modern browsers.

You can import jsdiff-es directly from a CDN or a hosting service like GitHub Pages.

import { diffChars } from "https://taisukef.github.io/jsdiff-es/src/diff/character.js";

const one = 'beep boop';
const other = 'beep boob blah';

const diff = diffChars(one, other);

console.log(diff);
// [
//   { value: 'beep boo', count: 8 },
//   { value: 'p', count: 1, removed: true },
//   { value: 'b blah', count: 6, added: true }
// ]

First, install the package:

npm install diff

Then, import and use the desired methods:

import { diffChars } from 'diff';
// or for CommonJS: const Diff = require('diff');

const one = 'beep boop';
const other = 'beep boob blah';

const diff = diffChars(one, other);

diff.forEach((part) => {
  // green for additions, red for deletions
  // grey for common parts
  const color = part.added ? 'green' :
    part.removed ? 'red' : 'grey';
  process.stderr.write(part.value[color]);
});

console.log();

This will produce a color-coded output in the terminal.

All diff methods return an array of change objects.

Change objects are the core return value and have the following structure:

• value (string): The content of the change.
• added (boolean | undefined): true if the value was inserted into the new string.
• removed (boolean | undefined): true if the value was removed from the old string.
• count (number | undefined): The number of tokens in the value.

If a change object has neither added nor removed set, it is a common part of both strings.

• diffChars(oldStr, newStr[, options]): Diffs two blocks of text, comparing character by character.
• diffWords(oldStr, newStr[, options]): Diffs two blocks of text, comparing word by word, ignoring whitespace.
• diffWordsWithSpace(oldStr, newStr[, options]): Diffs two blocks of text, comparing word by word, treating whitespace as significant.
• diffLines(oldStr, newStr[, options]): Diffs two blocks of text, comparing line by line.
• diffTrimmedLines(oldStr, newStr[, options]): Diffs two blocks of text, comparing line by line, ignoring leading and trailing whitespace.
• diffSentences(oldStr, newStr[, options]): Diffs two blocks of text, comparing sentence by sentence.

• diffCss(oldStr, newStr[, options]): Diffs two blocks of text, comparing CSS tokens.
• diffJson(oldObj, newObj[, options]): Diffs two JSON objects. The input will be canonicalized and pretty-printed, and then a line-based diff is performed.
• diffArrays(oldArr, newArr[, options]): Diffs two arrays, comparing each item for strict equality (===). An optional comparator function can be passed in the options object.

• createPatch(fileName, oldStr, newStr, oldHeader, newHeader[, options]): Creates a unified diff patch.
• createTwoFilesPatch(oldFileName, newFileName, oldStr, newStr, oldHeader, newHeader[, options]): Creates a unified diff patch for two separate files.
• structuredPatch(oldFileName, newFileName, oldStr, newStr, oldHeader, newHeader, options): Returns an object with an array of hunk objects.
• applyPatch(source, patch[, options]): Applies a unified diff patch.
• applyPatches(patch, options): Applies one or more patches.
• parsePatch(diffStr): Parses a patch into a structured data object.
• merge(mine, theirs, base): Merges two patches into a single result.

• convertChangesToXML(changes): Converts a list of change objects to a serialized XML format.
• convertChangesToDMP(changes): Converts a list of change objects to the Diff-Match-Patch format.

MIT License — see LICENSE.