pre

preprocessor

A JavaScript source file preprocessor in pure JavaScript, e.g. to build different versions of a library.

Showing:

Popularity

Downloads/wk

930

GitHub Stars

70

Maintenance

Last Commit

7yrs ago

Contributors

4

Package

Dependencies

1

Size (min+gzip)

9.5KB

License

Apache-2.0

Type Definitions

Tree-Shakeable

No?

Categories

Readme

Preprocessor.js - A JavaScript preprocessor

Provides a JavaScript source file preprocessor, e.g. to build different versions of a library. It's for example used to build ProtoBuf.js (its build and main script are quite good examples).

Deprecation notice: Preprocessor.js has been deprecated in favor of MetaScript, a much more JavaScripty way for build time meta programming using JavaScript itself as the meta language. Check out the migration guide to get a quick impression of its merits.

Directives

  • Includes (always relative to the baseDirectory, defaults to "."):

    ...
    // #include "path/to/file.js"
    ...
    
  • Static conditions:

    // #ifdef FULL
    console.log("Including extension");
    // #include "path/to/extension.js"
    // #else
    console.log("Not including extension");
    // #endif
    
  • Inverse static conditions:

    // #ifndef FULL
    console.log("Not including extension");
    // #else
    console.log("Including extension");
    // #include "path/to/extension.js"
    // #endif
    
  • Evaluable conditions:

    // #if 1==2
    console.log("1==2");
    // #elif 2==2
    console.log("2==2");
    // #endif
    
  • Inline variables and functions:

    // #define var PI=Math.PI
    // #define function RADTODEG(x){return x*180/PI}
    var angle = // #put RADTODEG(3)+";"
    
  • Writing the result of evaluated expressions:

    var version = // #put '"'+VERSION+'";"'
    var str = // #put "\"Hello world!\";"
    var onePlusOne = // #put (1+1)+";"
    

Features

  • CommonJS compatible
  • RequireJS/AMD compatible
  • Shim compatible (include the script, then use var ByteBuffer = dcodeIO.ByteBuffer;)
  • node.js compatible, also available via npm
  • Closure Compiler ADVANCED_OPTIMIZATIONS compatible (fully annotated, Preprocessor.min.js has been compiled this way, Preprocessor.min.map is the source map)
  • Fully documented using jsdoc3
  • Well tested through nodeunit
  • Zero production dependencies
  • Small footprint

Command line utility

Install via npm: npm -g install preprocessor

Command line

Usage: preprocess sourceFile [baseDirectory] [-myKey[=myValue], ...] [> outFile]

preprocess Source.js . -FULL=true > Source.full.js

API

The API is quite simple:

var result = new Preprocessor(
    mainFileSource,
    baseDirectoryOrIncludes
).process(defines);

with baseDirectoryOrIncludes being either a string containing the path to the base directory or an object of included sources by filename. When running in a browser, only the later is supported.

node.js / CommonJS

var Preprocessor = require("preprocessor");
var source = "..."; // e.g. through fs.readFile
var pp = new Preprocessor(source, ".");
console.log(pp.process({
    FULL: true
}));

RequireJS / AMD

require(["/path/to/Preprocessor.js"], function(Preprocessor) {
    var source = "..."; // e.g. through fs.readFile / $.ajax
    var pp = new Preprocessor(source, ".");
    console.log(pp.process({
        FULL: true
    }));
});

Browser / shim

Note: To use the #include directive in the browser, do not specify the base directory but an object of included sources by filename:

<script src="//raw.github.com/dcodeIO/Preprocessor.js/master/Preprocessor.min.js"></script>
var Preprocessor = dcodeIO.Preprocessor;
var source = "..."; // e.g. through. $.ajax
var pp = new Preprocessor(source, {
    "./includes/extension.js": "var myVar = 2;" // <- #include "includes/extension.js"
});
alert(pp.process({
    FULL: true
}));

Using includes instead of a base directory like shown in the example above is supported regardless of the platform you are on.

Downloads

Documentation

Tests (& Examples) Build Status

License

Apache License, Version 2.0 - http://www.apache.org/licenses/LICENSE-2.0.html

Rate & Review

Great Documentation0
Easy to Use0
Performant0
Highly Customizable0
Bleeding Edge0
Responsive Maintainers0
Poor Documentation0
Hard to Use0
Slow0
Buggy0
Abandoned0
Unwelcoming Community0
100
No reviews found
Be the first to rate

Alternatives

No alternatives found

Tutorials

No tutorials found
Add a tutorial