File comparison tool to accurately diff between file versions regardless of comments or minification to the whitespace. It can also beautify (pretty print) and minify HTML.

npm install prettydiff
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Pretty Diff

Try it online at or join the mailing list.


Please feel free to use file to supplement dom.js. Otherwise, dom.js requires supplemental assistance to map DOM nodes from an HTML source to the properties of the pd.o object found in dom.js. dom.js is fault tolerant so most of the nodes mapped by pd.o need not be supported from custom HTML.

To run Pretty Diff using dom.js include the following two script tags and bind the pd.recycle() function to the executing event. Please refer to for an HTML example and documentation.xhtml for option and execution information.

<script type="application/javascript" src="prettydiff.js"></script>
<script type="application/javascript" src="api/dom.js"></script>

Node.js / CommonJS / RequireJS

Node.js support is provided by api/node-local.js. This file can execute in the following modes:

  • screen - code input is on the command line and output is to the command line
  • filescreen - code input is in a file and the output is to the command line
  • file - the input and the output reside in files
  • directory - everything in a directory is processed into a specified output directory except ".", "..", and subdirectories

In your Node.js script include Pretty Diff with this code:

var prettydiff = require("prettydiff");

From the command line execute api/node-local.js similar to these examples:

>node c:\\prettydiff\\api\\node-local.js source:"c:\mydirectory\myfile.js" readmethod:"file" diff:"c:\myotherfile.js"

>node c:\\prettydiff\\api\\node-local.js source:"c:\mydirectory\myfile.js" mode:"beautify" readmethod:"file" output:"c:\output\otherfile.js"


Create a WSH script file using XML syntax and with a file extension of "WSF". This file must have a tag for each supported argument, must be capable of reading from a file, and retrieving dependencies.

Pretty Diff would be executed using the following on CLI:

cscript prettydiff.wsf
cscript prettydiff.wsf /source:"myFile.xml" /mode:"beautify"


  • The component files are provided for access to individual functions independent of the Pretty Diff application. The component code is already included in prettydiff.js, so it is not needed in addition to prettydiff.js. The only files not included with prettydiff.js are the APIs and the stylesheet - diffview.css.

  • For usage documentation please visit



@licstart The following is the entire license notice for the JavaScript code in this page.

Created by Austin Cheney originally on 3 Mar 2009. This code may not be used or redistributed unless the following conditions are met:

There is no licensing associated with diffview.css. Please use, redistribute, and alter to your content. However, diffview.css provided from Pretty Diff is different from and not aligned with diffview.css originally from Snowtide Informatics.

  • The code mentioned above has significantly expanded documentation in each of the respective function's external JS file as linked from the documentation page:

  • The compilation of cssClean, csvbeauty, csvmin, jsmin, jsdifflib, markup_beauty, markupmin, and js-beautify in this manner is a result of the prettydiff() function contained in prettydiff.js. The per character highlighting is the result of the charcomp() function also contained in prettydiff.js. Any use or redistribution of these functions must mention the following: Prettydiff created by Austin Cheney originally on 3 Mar 2009.

    Join the Pretty Diff mailing list at:

  • In addition to the previously stated requirements any use of any component, aside from directly using the full files in their entirety, must restate the license mentioned at the top of each concerned file.

If each and all these conditions are met use and redistribution of prettydiff and its required assets is unlimited without author permission.

@licend The above is the entire license notice for the JavaScript code in this page.


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