I completely rebuilt the jsdifflib utility for speed. Since my version does not require DOM access it at least 4.5 times faster, and it is also extended to highlight character differences in each line.

http://prettydiff.com/diffview.js

You can test this out with the online tool directly at http://prettydiff.com/

Answer from austincheney on Stack Overflow
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GitHub
github.com › kpdecker › jsdiff
GitHub - kpdecker/jsdiff: A javascript text differencing implementation. · GitHub
A javascript text differencing implementation. Contribute to kpdecker/jsdiff development by creating an account on GitHub.
Starred by 9.1K users
Forked by 525 users
Languages   JavaScript 64.7% | TypeScript 35.3%
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npm
npmjs.com › search
jsdiff - npm search
A JavaScript text diff implementation.
People also ask

What is JSDiff?
JSDiff is a free online tool for comparing JSON and JavaScript code. It uses the Myers Difference Algorithm to highlight differences between two text segments, making it easy to see what has been added, removed, or modified.
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jsdiff.com
jsdiff.com › home
JSON Diff - The semantic JSON compare tool - JavaScript Text Diff ...
Is JSDiff free to use?
Yes, JSDiff is completely free to use. All processing is done locally in your browser, ensuring your data remains private and secure.
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jsdiff.com
jsdiff.com › home
JSON Diff - The semantic JSON compare tool - JavaScript Text Diff ...
Is my data safe when using JSDiff?
Yes, all data processing happens locally in your browser. No data is sent to any server, ensuring complete privacy and security.
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jsdiff.com
jsdiff.com › home
JSON Diff - The semantic JSON compare tool - JavaScript Text Diff ...
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GitHub
github.com › cemerick › jsdifflib
GitHub - cemerick/jsdifflib: A javascript library for diffing text and generating corresponding HTML views · GitHub
It’s been sequestered (mostly out of simple neglect) to my company’s servers for too long; now that it’s on github, I’m hoping that many of the people that find it useful will submit pull requests to improve the library. I will do what I can to curate that process. jsdifflib carries a BSD license. As such, it may be used in other products or services with appropriate attribution (including commercial offerings). The license is prepended to each of jsdifflib’s files. jsdifflib consists of three files — two Javascript files, and one CSS file. Why two Javascript files? Because I wanted to keep the reimplementation of the python difflib.SequenceMatcher class separate from the actual visual diff view generator.
Starred by 1.5K users
Forked by 263 users
Languages   JavaScript 88.1% | CSS 11.9%
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JSDiff
jsdiff.com › home
JSON Diff - The semantic JSON compare tool - JavaScript Text Diff Library | Myers Algorithm Implementation
JSDiff is a free online tool designed specifically for developers. It helps you quickly compare the differences between two segments of JSON or JavaScript code, supporting highlighted display, structured presentation, and one-click merging.
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GitHub
github.com › rtfpessoa › diff2html
GitHub - rtfpessoa/diff2html: Pretty diff to html javascript library (diff2html) · GitHub
Import the stylesheet and the library code. To load correctly in the Browser you need to include the stylesheet in the final HTML. <!-- CSS --> <link rel="stylesheet" type="text/css" href="https://cdn.jsdelivr.net/npm/diff2html/bundles/css/diff2html.min.css" /> <!-- Javascripts --> <script type="text/javascript" src="https://cdn.jsdelivr.net/npm/diff2html/bundles/js/diff2html.min.js"></script> It will now be available as a global variable named Diff2Html.
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Languages   TypeScript 88.0% | Handlebars 5.7% | CSS 4.1% | HCL 1.0% | Mustache 0.8% | JavaScript 0.4%
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Hacker News
news.ycombinator.com › item
The fastest object diff library in JavaScript | Hacker News
November 7, 2021 - Seems that this particular library is aware of these potential issues (which motivated me to write this comment): https://github.com/AsyncBanana/microdiff/issues/2 · It's a good point about edge cases in diffing. Dynamic value diffing in dynamically-typed languages is an interesting problem ...
Find elsewhere
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npm
npmjs.com › package › diff
diff - npm
A JavaScript text diff implementation.. Latest version: 8.0.3, last published: 2 months ago. Start using diff in your project by running `npm i diff`. There are 8153 other projects in the npm registry using diff.
      » npm install diff
    
Published   Jan 12, 2026
Version   8.0.3
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Qiao
qiao.github.io › difflib.js
Difflib.js by qiao
A JavaScript module which provides classes and functions for comparing sequences. It can be used for example, for comparing files, and can produce difference information in various formats, including context and unified diffs.
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GitHub
github.com › google › diff-match-patch
GitHub - google/diff-match-patch: Diff Match Patch is a high-performance library in multiple languages that manipulates plain text. · GitHub
Compare two blocks of plain text and efficiently return a list of differences. ... Given a search string, find its best fuzzy match in a block of plain text. Weighted for both accuracy and location. ... Apply a list of patches onto plain text. Use best-effort to apply patch even when the underlying text doesn't match. ... Originally built in 2006 to power Google Docs, this library is now available in C++, C#, Dart, Java, JavaScript, Lua, Objective C, and Python.
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Languages   Python 17.0% | Objective-C 14.4% | Dart 12.2% | C++ 11.1% | C# 11.1% | Java 10.8%
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Reddit
reddit.com › r/webdev › i created the fastest object and array diff library in javascript
r/webdev on Reddit: I created the fastest object and array diff library in JavaScript
November 6, 2021 - JsDiff - Visual comparison of javascript libraries! ... Chat about javascript and javascript related projects. Yes, typescript counts.
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Mergely
mergely.com › about
About Mergely JavaScript library
Mergely is a powerful online diff and merge editor and javascript library that highlights changes in text. It can be embedded within your own Web application to compare files, text, C, C++, Java, HTML, XML, CSS, and javascript. Refer to the documentation for information on how to use Mergely.
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npm
npmjs.com › package › deep-object-diff
deep-object-diff - npm
A small library that can deep diff two JavaScript Objects, including nested structures of arrays and objects.
      » npm install deep-object-diff
    
Published   Nov 12, 2022
Version   1.1.9
Author   Matt Phillips
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GitHub
github.com › liddiard › text-diff
GitHub - liddiard/text-diff: Visual JavaScript text diff library. CommonJS module created from https://code.google.com/p/google-diff-match-patch/.
Visual JavaScript text diff library. CommonJS module created from https://code.google.com/p/google-diff-match-patch/. - liddiard/text-diff
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Languages   JavaScript 100.0% | JavaScript 100.0%
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HackerNoon
hackernoon.com › introducing-a-new-javascript-library-for-object-diffing-and-patching
Introducing a New JavaScript Library for Object Diffing and Patching | HackerNoon
May 1, 2024 - Open Tech Foundation introduces a new JavaScript library to assist with object diffing and patching. Demos and more are included.
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CodePen
codepen.io › jasondavis › pen › adLEqN
Diff JavaScript LIbrary to view Diff + and - between 2 text strings
<!-- Header Block --> <div id="pen-header-wrap"> <div id="pen-header"> <div id="pen-title"> Diff JavaScript LIbrary to view Diff + and - between 2 text strings</div> <div id="pen-description"> <span>Description:</span><br> Diff, Match and Patch: Demo of Diff<br> Find the Diff (additions and subtractions between 2 text strings just like StackOverflow Editor versions and WOrdPress post versions show)<br> <img src="https://www.apollowebstudio.com/screenshots/2016/Diff,_Match_and_Patch_Demo_of_Diff_-_Google_Chrom_2016-01-16_05-42-37.png"> </div> <div id="pen-notes"> <span>Notes/Comments:</span> te
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diff2html
diff2html.xyz
diff2html
GraphQL Schema Diff · Detects dangerous and breaking changes in GraphQL schemas. cypress-plugin-snapshots · Plugin for snapshot tests in Cypress.io. git-explorer · Offline-first support for previewing local git repositories. edgar-monitor · A module that processes new Edgar filings and sends out notifications. Simple Git · A simple package to be able to drive GIT. jsreport · javascript based business reporting platform ·
Author   Rodrigo Fernandes
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GitHub
github.com › cosmicanant › recursive-diff
GitHub - cosmicanant/recursive-diff: A JavaScript library to find diff between two JavaScript Objects. Support for Array, Number, Date and other primitive data types.
A JavaScript library to find diff between two JavaScript Objects. Support for Array, Number, Date and other primitive data types. - cosmicanant/recursive-diff
Starred by 153 users
Forked by 21 users
Languages   JavaScript 100.0% | JavaScript 100.0%