broccoli-filter
v1.3.0
Published
Helper base class for Broccoli plugins that map input files into output files one-to-one
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broccoli-filter
Helper base class for Broccoli plugins that map input files into output files one-to-one.
API
class Filter {
/**
* Abstract base-class for filtering purposes.
*
* Enforces that it is invoked on an instance of a class which prototypically
* inherits from Filter, and which is not itself Filter.
*/
constructor(inputNode: BroccoliNode, options: FilterOptions): Filter;
/**
* Abstract method `processString`: must be implemented on subclasses of
* Filter.
*
* The return value is written as the contents of the output file
*/
abstract processString(contents: string, relativePath: string): string;
/**
* Virtual method `getDestFilePath`: determine whether the source file should
* be processed, and optionally rename the output file when processing occurs.
*
* Return `null` to pass the file through without processing. Return
* `relativePath` to process the file with `processString`. Return a
* different path to process the file with `processString` and rename it.
*
* By default, if the options passed into the `Filter` constructor contain a
* property `extensions`, and `targetExtension` is supplied, the first matching
* extension in the list is replaced with the `targetExtension` option's value.
*/
virtual getDestFilePath(relativePath: string): string;
}
Options
extensions
: An array of file extensions to process, e.g.['md', 'markdown']
.targetExtension
: The file extension of the corresponding output files, e.g.'html'
.inputEncoding
: The character encoding used for reading input files to be processed (default:'utf8'
). For binary files, passnull
to receive aBuffer
object inprocessString
.outputEncoding
: The character encoding used for writing output files after processing (default:'utf8'
). For binary files, passnull
and return aBuffer
object fromprocessString
.name
,annotation
: Same as broccoli-plugin; see there.
All options except name
and annotation
can also be set on the prototype
instead of being passed into the constructor.
Example Usage
var Filter = require('broccoli-filter');
Awk.prototype = Object.create(Filter.prototype);
Awk.prototype.constructor = Awk;
function Awk(inputNode, search, replace, options) {
options = options || {};
Filter.call(this, inputNode, {
annotation: options.annotation
});
this.search = search;
this.replace = replace;
}
Awk.prototype.extensions = ['txt'];
Awk.prototype.targetExtension = 'txt';
Awk.prototype.processString = function(content, relativePath) {
return content.replace(this.search, this.replace);
};
In Brocfile.js
, use your new Awk
plugin like so:
var node = new Awk('docs', 'ES6', 'ECMAScript 2015');
module.exports = node;
FAQ
Upgrading from 0.1.x to 1.x
You must now call the base class constructor. For example:
// broccoli-filter 0.1.x:
function MyPlugin(inputTree) {
this.inputTree = inputTree;
}
// broccoli-filter 1.x:
function MyPlugin(inputNode) {
Filter.call(this, inputNode);
}
Note that "node" is simply new terminology for "tree".
Source Maps
Can this help with compilers that are almost 1:1, like a minifier that takes
a .js
and .js.map
file and outputs a .js
and .js.map
file?
Not at the moment. We don't know yet how to implement this and still have the
API look beautiful. Such cases complicate the caching logic, as we have to make
sure to rebuild a file if either the .js
or the .js.map
file changes.
For now, your best bet is the broccoli-multifilter plugin base class.