Preprocess HTML, JavaScript, and other files with directives based off custom or ENV configuration
<head>
<title>Your App</title>
<!-- @if NODE_ENV='production' -->
<script src="some/production/lib/like/analytics.js"></script>
<!-- @endif -->
</head>
<body>
<!-- @ifdef DEBUG -->
<h1>Debugging mode - <!-- @echo RELEASE_TAG --> </h1>
<!-- @endif -->
<p>
<!-- @include welcome_message.txt -->
</p>
</body>var configValue = '/* @echo FOO */' || 'default value';
// @ifdef DEBUG
someDebuggingCall()
// @endifThe most basic usage is for files that only have two states, non-processed and processed.
In this case, your @exclude directives are removed after preprocessing
<body>
<!-- @exclude -->
<header>You're on dev!</header>
<!-- @endexclude -->
</body>After build
<body>
</body>@if VAR='value'/@endifThis will include the enclosed block if your test passes@ifdef VAR/@endifThis will include the enclosed block if VAR is defined (typeof !== 'undefined')@ifndef VAR/@endifThis will include the enclosed block if VAR is not defined (typeof === 'undefined')@includeThis will include the source from an external file. If the included source ends with a newline then the following line will be space indented to the level the @include was found. Requires thesrcDircontext attribute to point to the source dir of the files to be included, i.e.{srcDir: '.'}.@include-staticWorks the same way as@includebut doesn't process the included file recursively. Is useful if a large file has to be included and the recursive processing is not necessary or would otherwise take too long. Requires thesrcDircontext attribute to point to the source dir of the files to be included, i.e.{srcDir: '.'}.@extend file.html/@endextendThis will use the source from the external file indicated with the@extendtag to wrap the enclosed block. Requires thesrcDircontext attribute to point to the source dir of the file to be extended, i.e.{srcDir: '.'}.@extendableThis tag is used to indicate the location in a file referenced using@extendwhere the block enclosed by@extendwill be populated.@exclude/@endexcludeThis will remove the enclosed block upon processing@echo VARThis will include the environment variable VAR into your source@foreach $VAR in ARR/@endforThis will repeat the enclosed block for each value in the Array or Object in ARR. Each value in ARR can be interpolated into the resulting content with $VAR.@exec FUNCTION([param1, param2...])This will execute the environment FUNCTION with its parameters and echo the result into your source. The parameter could be a string or a reference to another environment variable.
This is useful for more fine grained control of your files over multiple environment configurations. You have access to simple tests of any variable within the context (or ENV, if not supplied)
<body>
<!-- @if NODE_ENV!='production' -->
<header>You're on dev!</header>
<!-- @endif -->
<!-- @if NODE_ENV='production' -->
<script src="some/production/javascript.js"></script>
<!-- @endif -->
<script>
var fingerprint = '<!-- @echo COMMIT_HASH -->' || 'DEFAULT';
</script>
<script src="<!-- @exec static_path('another/production/javascript.js') -->"></script>
</body>With a NODE_ENV set to production and 0xDEADBEEF in
COMMIT_HASH this will be built to look like
<body>
<script src="some/production/javascript.js"></script>
<script>
var fingerprint = '0xDEADBEEF' || 'DEFAULT';
</script>
<script src="http://cdn2.my.domain.com/another/javascript.js"></script>
</body>With NODE_ENV not set or set to dev and nothing in COMMIT_HASH, the built file will be
<body>
<header>You're on dev!</header>
<script>
var fingerprint = '' || 'DEFAULT';
</script>
<script src="http://localhost/myapp/statics/another/javascript.js"></script>
</body>You can also have conditional blocks that are hidden by default by using the
fictional !> end tag instead of --> after your condition:
<!-- @if true !>
<p>Process was run!</p>
<!-- @endif -->Extended syntax below, but will work without specifying a test
normalFunction();
//@exclude
superExpensiveDebugFunction()
//@endexclude
'/* @echo USERNAME */'
anotherFunction();Built with a NODE_ENV of production :
normalFunction();
'jsoverson'
anotherFunction();Like HTML, you can have conditional blocks that are hidden by default by ending the directive with a ** instead of */
angular.module('myModule', ['dep1'
, 'dep2'
/* @if NODE_ENV='production' **
, 'prod_dep'
/* @endif */
/* @exclude **
, 'debug_dep'
/* @endexclude */
]);Note: Hidden by default blocks only work with block comments (/* */) but not with line comments (//).
CSS example
body {
/* @if NODE_ENV=='development' */
background-color: red;
/* @endif */
}
// @include util.css(CSS preprocessing supports single line comment style directives)
#!/bin/bash
# @include util.sh
Install via npm
$ npm install --save preprocessUse the exposed preprocess method or the convenience file functions. The context, by default, is the
current ENV config the process (process.env)
var pp = require('preprocess');
var text = 'Hi, I am <!-- @echo USERNAME -->';
pp.preprocess(text);
// -> Hi, I am jsoverson
pp.preprocess(text, {USERNAME : "Bob"});
// -> Hi, I am Bob
// specify the format to use for the directives as the third parameter
pp.preprocess(text, {USERNAME : "Bob"}, 'html');
// -> Hi, I am Bob
// Simple wrapper around fs.readFile and fs.writeFile
pp.preprocessFile(src, dest, context, callback);
// Simple wrapper around fs.readFileSync and fs.writeFileSync
pp.preprocessFileSync(src, dest, context);In lieu of a formal styleguide, take care to maintain the existing coding style. Add unit tests for any new or changed functionality. Lint and test your code using jshint
- 2.4.0
- All block directives (ones that have a start and an end token, like
@if/@endif) are now processed recursively (via @Frizi, #61) - Added hidden by default configuration blocks for js (via @mallowigi, #40)
- fixed
@execin files included via@includeand@extend(fixes #58) - changed
@extendand@excludehtml regex so that directives may appear more than once in one line (fixes #36) - fixed multiple issues with coffescript syntax (fixes #39)
- fixed multiple issues with newlines (fixes #8)
- All block directives (ones that have a start and an end token, like
- 2.3.1 Fixed @echo and @exec directives to allow
-and*characters (fixes #21, #45, #51), fixed @exec with multiple params (fixes #54). - 2.3.0 Added support for @include-static
- 2.2.0 Added support for @foreach and @extend
- 2.1.1 Added support for .styl files via js regex (via @nsonnad)
- 2.1.0 Added automatic support for numerous formats, merged @exec, hidden by default html tags, added simple directives
- 2.0.0 Added ability to echo strings, added conditional comments, removed lodash, merged 17, 13, 15, 16
- 1.2.0 Added processing for hash-style comments (via @marsch). Added more file aliases.
- 1.1.0 Added deep inclusion, fixed sequential ifs
- 1.0.1 Fixed multiple inline echo statements
- 1.0.0 Pulled from grunt-preprocess to stand alone
Copyright Jarrod Overson
Written by Jarrod Overson
Licensed under the Apache 2.0 license.