jsmake: a simple javascript preprocessor in perl

In the previous post I listed some javascript preprocessors you could find out there...
But could not find any written in perl...
And could not find a preprocessor that could handle package dependencies...
Therefore,I've taken a day to hack a command line utility to use as a basic preprocessor for javascript.
Only tested on my mac, it's a dirty, huge perl file but it might help some people out there until there's a real project to build a javascript preprocessor in perl.

Functionality

This utility can:

- compress the javascript files with 3 different algorithms:

Javascript::Mini
Javascript::Packer
Google online closure application

- load and merge files in order of dependency:

jsmake follows package rules used by perl or actionscript language.
It transpose the package name into a folder tree. Therefore:

Core.Util.Array

is understood as Core/Util/Array.js.

You can specify the dependeny at the very first line of your javascript file in a comment as follow:

/*!require: Core.Util.String,Core.Util.Queue */

jsmake will load all the dependencies in all the files in the right order.

- parse the javascript source file for some directives.

ifdef, ifndef, end, define are understood:

/*@ifdef DEBUG */
console.log("debug mode");
/*@end */


/*@ifndef DEBUG */
console.log("not in debug mode");
/*@end */

or if you like # better:


/*#ifndef DEBUG */
console.log("not in debug mode");
/*#end */

/*@define VERSION 1.06 */

How to use

on the terminal, just type:

$ jsmake

if you do not need any options just make the file executable.

There are obviously command line options:

input

$ jsmake -input ../lib

This tells where to look for the javascript to be merged/preprocessed/smashed.

output

$ jsmake -output ../src/merged.js

This tells where to output the final merged output.

compression

$ jsmake -compression name


Example:
$ jsmake -compression mini

This tells what kind of compression it should use.
There are 3 different compressors for now:

• packer
• mini
• closure

Closure use google online closure service with the least aggressive algorithm.
So... you just need to be connected to the internet to use this one.
packer and mini requires perl modules to be installed, respectively JavaScript::Packer and JavaScript::Minifier.

Using the compression will output 2 files:
the one uncompressed and the one compressed prefixed with the name of the compression type, so it might be output.js and closure-output.js

packages

$ jsmake -packages name separated by a space

Example:
$ jsmake -packages Core.DOM Core.Util.String

If you do not specify a package jsmake will merge all the files that contain the !require: directive.
By specifying the package name,jsmake will only merge the file necessary for this package to work as defined in your dependencies.

vars

$ jsmake -vars name separated by a space

Example:
$ jsmake -vars DEBUG STRICT_MODE

By specifying the name of some variables, you will make them come true.
Therefore all the ifdef or ifndef will be stripped down accordingly.
if you want a STRICT_MODE but no DEBUG messages, you will write:
$ jsmake -vars STRICT_MODE

define

$ jsmake -define name=value variable name=value

Example:
$ jsmake -define VERSION=6.01 AUTHOR=myself

vars allows you to overwrite the one inline in your javascript file.
So if you define in your javascript /#define VERSION 3.01 / but at the command line
set the variable to 6.01, the final output will be 6.01
Will look into merging vars and define functionality into one as it is confusing...

That's it!!

so if we go for a full option set up, you can get:

$ jsmake -input ../lib -output ../src/merged.js -packages Core.DOM Core.Util.String -vars DEBUG -define VERSION=6.12 AUTHOR=myself -compression mini

This will create two files merged.js and mini-merged.js compressed, cleaned out and with all the dependencies.

Download & Doc

http://code.google.com/p/jsmake-preprocessor/

Hope this is useful too somebody and that you won't be too hard on my perl capacities. Comment to improve the code welcome!