preprocess

Preprocess directives in HTML, JavaScript, etc directives based off variable context

Downloads in past

Stats

StarsIssuesVersionUpdatedCreatedSize
preprocess
3.2.04 years ago11 years agoMinified + gzip package size for preprocess in KB

Popular Searches

Readme

preprocess
!NPMnpm-imagenpm-url
!Linux Build Statuslinux-ci-imagelinux-ci-url !Windows Build Statuswindows-ci-imagewindows-ci-url !Coverage Statuscoverage-imagecoverage-url !dependenciesdeps-imagedeps-url !dev-dependenciesdev-deps-imagedev-deps-url
Preprocess HTML, JavaScript, and other files with directives based off custom or ENV configuration

Configuration

Install via npm:
$ npm install --save preprocess

What does it look like?

<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()
// @endif

Directive syntax

Basic example

The 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>

All directives

- @if VAR='value' / @endif
This will include the enclosed block if your test passes
- @ifdef VAR / @endif
This will include the enclosed block if VAR is defined (typeof !== 'undefined')
- @ifndef VAR / @endif
This will include the enclosed block if VAR is not defined (typeof === 'undefined')
- @include
This 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.
- @include-static
Works the same way as `@include` but 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.
- @extend file.html / @endextend
This will use the source from the external file indicated with the `@extend` tag to wrap the enclosed block.
- @extendable
This tag is used to indicate the location in a file referenced using `@extend` where the block enclosed by `@extend` will be populated.
- @exclude / @endexclude
This will remove the enclosed block upon processing
- @echo VAR
This will include the environment variable VAR into your source
- @foreach $VAR in ARR / @endfor
This 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.

Extended html Syntax

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 NODEENV not set or set to dev and nothing in COMMITHASH, 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 -->

JavaScript, CSS, C, Java Syntax

Extended syntax below, but will work without specifying a test
normalFunction();
//@exclude
superExpensiveDebugFunction()
//@endexclude

anotherFunction('/* @echo USERNAME */');

Built with a NODEENV of production :
normalFunction();

anotherFunction('jsoverson');

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)

Shell, PHP

#!/bin/bash

# @include util.sh

API

preprocess(source, context, options) -> preprocessedSource

Preprocesses a source provided as a string and returns the preprocessed source.

source

Type: String (mandatory)
The source to preprocess.

context

Type: Object Default: process.env
The context that contains the variables that are used in the source. For @extend variants and @include the additional context property src is available inside of files to be included that contains the current file name. This property is also available in the context of the source file if one of the preprocessFile*() API variants are used.

options

Type: Object
The options object allows to pass additional options to preprocess. Available options are:
options.fileNotFoundSilentFail
Type: Boolean Default: false
When using @include variants and @extend, preprocess will by default throw an exception in case an included file can't be found. Set this option to true to instruct preprocess to fail silently and instead of throwing to write a message inside of the preprocessed file that an included file could not be found.
options.srcDir
Type: String Default: process.cwd()
The directory where to look for files included via @include variants and @extend.
options.srcEol
Type: String Default: EOL of source string or os.EOL if source string contains multiple different or no EOLs.
The end of line (EOL) character to use for the preprocessed result. May be one of: - \r\n - Windows - \n - Linux/OSX/Unix - \r - legacy Mac
options.type
Type: String Default: html
The syntax type of source string to preprocess. There are 3 main syntax variants: - html, aliases: xml - js, aliases: javascript, jsx, json, c, cc, cpp, cs, csharp, java, less, sass, scss, css, php,
`ts`, `tsx`, `peg`, `pegjs`, `jade`, `styl`
- coffee, aliases: bash, shell, sh

preprocessFile(srcFile, destFile, context, callback, options)

Preprocesses a sourceFile and saves the result to destFile. Simple wrapper around fs.readFile() and fs.writeFile().

srcFile

Type: String (mandatory)
The path to the source file to preprocess.

destFile

Type: String (mandatory)
The path to the destination file where the preprocessed result shall be saved.

context

See context attribute description of preprocess() function.

callback

Type: function(err)
The callback function that is called upon error or completion. Receives an error if something goes wrong as first parameter.

options

See options attribute description of preprocess() function. Differs only in that the default srcDir value is set to the path of the provided source file instead of process.cwd() and the default type is derived from source file extension.

preprocessFileSync(srcFile, destFile, context, options)

Preprocesses a sourceFile and saves the result to destFile. Simple wrapper around fs.readFileSync() and fs.writeFileSync().

srcFile

Type: String (mandatory)
The path to the source file to preprocess.

destFile

Type: String (mandatory)
The path to the destination file where the preprocessed result shall be saved.

context

See context attribute description of preprocess() function.

options

See options attribute description of preprocess() function. Differs only in that the default srcDir value is set to the path of the provided source file instead of process.cwd() and the default type is derived from source file extension.

Usage Examples

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"}, {type: 'html'});
// -> Hi, I am Bob

// Preprocess files asynchronously
pp.preprocessFile(src, dest, context, callback, options);

// Preprocess files synchronously
pp.preprocessFileSync(src, dest, context, options);

Contributing

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

Release History

- 3.1.0
- Added `.jsx` file extension as an alias for `js` (@BendingBender, #79)
- Added `.tsx` file extension as an alias for `js` (@rosendi, #100)
- Bumped XRegExp to v3
- 3.0.1/2 Fixes for backward compatibility and regex cleanups (thanks to @anseki for suggestions, #77) - 3.0.0
Breaking changes:
- If a file requested by `@include` or `@extend` can not be found, `preprocess` will now throw by default
  with a possibility to opt in to the legacy behavior via the `fileNotFoundSilentFail` option (@BendingBender, #35).
- Fixed multiple issues with newlines (@BendingBender, #8), this may result in output that differs from earlier
  versions.
- The `srcDir` option was moved to the options object and now defaults to `process.cwd` instead of throwing by
  default (@BendingBender, #68)

New functionality:
- All block directives (ones that have a start and an end token, like `@if`/`@endif`) are now processed recursively (@Frizi, #61)
- Added hidden by default configuration blocks for `js` (@mallowigi, #40) and `html` (@Frizi, #66)

Fixes:
- fixed `@exec` in files included via `@include` and `@extend` (@BendingBender, #58)
- changed `@extend` and `@exclude` html regex so that directives may appear more than once in one line (@BendingBender, #36)
- fixed multiple issues with coffescript syntax (@BendingBender, #39)
- fixed `@if` and `@foreach` to not require trailing whitespace (@BendingBender, #74)
- 2.3.1 Fixed @echo and @exec directives to allow - and * characters, fixed @exec with multiple params (@BendingBender, #21, #45, #51, #54). - 2.3.0 Added support for @include-static (@BendingBender) - 2.2.0 Added support for @foreach and @extend (@orionstein) - 2.1.1 Added support for .styl files via js regex (@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 (@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

License

Copyright Jarrod Overson
Written by Jarrod Overson
Licensed under the Apache 2.0 license.