Preprocess directives in HTML, JavaScript, etc directives based off variable context
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Preprocess HTML, JavaScript, and other files with directives based off custom or ENV configuration
Install via npm:
``bash`
$ npm install --save preprocess
`html
js
var configValue = '/ @echo FOO /' || 'default value';// @ifdef DEBUG
someDebuggingCall()
// @endif
`Directive syntax
$3
The most basic usage is for files that only have two states, non-processed and processed.
In this case, your
directives are removed after preprocessing`html
You're on dev!
`After build
html
`$3
-
/ @endif
This will include the enclosed block if your test passes
- / @endif
This will include the enclosed block if VAR is defined (typeof !== 'undefined')
- / @endif
This will include the enclosed block if VAR is not defined (typeof === 'undefined')
-
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.
-
Works the same way as 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 tag to wrap the enclosed block.
- @extendable
This tag is used to indicate the location in a file referenced using where the block enclosed by @extend will be populated.
- @exclude / @endexclude
This will remove the enclosed block upon processing
-
This will include the environment variable VAR into your source
- / @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.
-
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.$3
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)
html
You're on dev!
`With a
set to production and 0xDEADBEEF in
COMMIT_HASH this will be built to look like`html
`With NODE_ENV not set or set to dev and nothing in COMMIT_HASH,
the built file will be
html
You're on dev!
`You can also have conditional blocks that are hidden by default by using the
fictional
end tag instead of --> after your condition:`html
`$3
Extended syntax below, but will work without specifying a test
js
normalFunction();
//@exclude
superExpensiveDebugFunction()
//@endexcludeanotherFunction('/ @echo USERNAME /');
`Built with a NODE_ENV of production :
js
normalFunction();anotherFunction('jsoverson');
`Like HTML, you can have conditional blocks that are hidden by default by ending the directive with a
instead of /js
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
`css
body {
/ @if NODE_ENV=='development' /
background-color: red;
/ @endif /}
// @include util.css
`(CSS preprocessing supports single line comment style directives)
$3
bash
#!/bin/bash@include util.sh
`API
$3
Preprocesses a source provided as a string and returns the preprocessed source.
#### source
Type:
(mandatory)The source to preprocess.
#### context
Type:
Object
Default: The context that contains the variables that are used in the source. For
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:
ObjectThe options object allows to pass additional options to
. Available options are:##### options.fileNotFoundSilentFail
Type:
Boolean
Default: When using
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: The directory where to look for files included via
variants and @extend.##### options.srcEol
Type:
String
Default: EOL of source string or 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: The syntax type of source string to preprocess. There are 3 main syntax variants:
-
, aliases: xml
- , aliases: javascript, jsx, json, c, cc, cpp, cs, csharp, java, less, sass, scss, css, php,
ts, tsx, peg, pegjs, jade, styl
- , aliases: bash, shell, sh$3
Preprocesses a
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
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.
$3
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
`js
var pp = require('preprocess');var text = 'Hi, I am ';
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 jshintRelease History
- 3.1.0
- Added 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).Copyright Jarrod Overson
Written by Jarrod Overson
Licensed under the Apache 2.0 license.
[npm-image]: https://nodei.co/npm/preprocess.png?downloads=true
[npm-url]: https://www.npmjs.com/package/preprocess
[linux-ci-image]: https://img.shields.io/travis/jsoverson/preprocess/master.svg?style=flat-square&label=Linux%20build
[linux-ci-url]: https://travis-ci.org/jsoverson/preprocess
[windows-ci-image]: https://img.shields.io/appveyor/ci/BendingBender/preprocess/master.svg?style=flat-square&label=Windows%20build
[windows-ci-url]: https://ci.appveyor.com/project/BendingBender/preprocess
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[deps-url]: https://david-dm.org/jsoverson/preprocess
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[dev-deps-url]: https://david-dm.org/jsoverson/preprocess#info=devDependencies
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[coverage-url]: https://coveralls.io/r/jsoverson/preprocess?branch=master