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How can I beautify JavaScript code using Command Line?

I am writing a batch script in order to beautify JavaScript code. It needs to work on both Windows and Linux.

How can I beautify JavaScript code using the command line tools?

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Answer

First, pick your favorite Javascript based Pretty Print/Beautifier. I prefer the one at http://jsbeautifier.org/, because it’s what I found first. Downloads its file https://github.com/beautify-web/js-beautify/blob/master/js/lib/beautify.js

Second, download and install The Mozilla group’s Java based Javascript engine, Rhino. “Install” is a little bit misleading; Download the zip file, extract everything, place js.jar in your Java classpath (or Library/Java/Extensions on OS X). You can then run scripts with an invocation similar to this

JavaScript

Use the Pretty Print/Beautifier from step 1 to write a small shell script that will read in your javascript file and run it through the Pretty Print/Beautifier from step one. For example

JavaScript

Rhino gives javascript a few extra useful functions that don’t necessarily make sense in a browser context, but do in a console context. The function print does what you’d expect, and prints out a string. The function readFile accepts a file path string as an argument and returns the contents of that file.

You’d invoke the above something like

JavaScript

You can mix and match Java and Javascript in your Rhino run scripts, so if you know a little Java it shouldn’t be too hard to get this running with text-streams as well.

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