revolver-webpack-plugin

Webpack plugin for relative path resolving from a list of directories.

Information

Webpack doesn't natively support changing the source directory of your files when including them using require or import. This plugin provides the ability to specify a list of directories that Webpack should read from before trying to resolve relative paths. Think of it as a fallback system.

This is useful when you need to resolve files across different directories if they exist, like when working with different themes or locales for a site and resolve.alias or resolve.modules won't work for your use case.

Let's say you have a containing file a.js that uses the following configuration on your source directory:

import * from './foo';
import * from './bar';
    
//Write some logic using these files...

But then on a separate build, theme, locale, or overlaying directory you want to override foo while keeping bar intact within the same containing file. Ideally you wouldn't want to duplicate the containing file a.js just to change the behavior of foo.

Using this plugin you can achieve exactly that, and more! Set a list of directories in the directoryList property, and revolve-webpack-plugin will resolve those directories in the specified order.

Install

Works with Webpack 2.x and up.

npm install revolver-webpack-plugin --save-dev

Usage

const path = require('path');
const revolverPlugin = require('revolver-webpack-plugin');

let customDir = path.resolve(__dirname, 'path/to/custom/directory'),
    srcDir = path.resolve(__dirname, 'path/to/src/directory');

let webpackConfig = {
    entry: '...',
    [...],
    resolve: {
        plugins: [
            new revolverPlugin({
                directoryList: [customDir, srcDir]
            })
        ],
    },
    [...]
}

Importing/requiring files

This plugin uses the default ES6/CommonJS/Webpack syntax for resolving files (i.e. ./, ../), which means no syntactical changes for how you require or import files are strictly necessary.

Whenever a relative path is specified, it will attempt to match that against the directoryList paths.

Examples

Assume your directoryList is set to: ['path/to/custom', 'path/to/src']

Say you have the structure shown below. Where src/a.js is an entry point or is another file's dependency, and imports src/foo.js and src/bar.js:

├── app
│   ├── custom
│   │   └── foo.js
│   └── src
│       ├── a.js
│       ├── bar.js
│       └── foo.js

When src/a.js is built, since we specified that custom has higher priority than src on our directoryList, and because there is a foo.js file in custom, it will import custom/foo.js and src/bar.js.

Now let's say you want to extend the functionalities of src/foo.js through custom/foo.js, you could achieve that the normal way:

//custom/foo.js
import * as foo from '../src/foo';

However that approach becomes cumbersome whenever you have multiple overlaying directories extending the same foo.js file, since you'd need to keep track of the order in which you're importing your files. To solve this you can use */, which tells revolver-webpack-plugin "import from the next directory in directoryList that contains a match":

//custom/foo.js
import * as foo from '*/foo'; //imports `src/foo`

In case you want to import a file from the next matching directory in directoryList (as opposed to letting revolver-webpack-plugin resolve the file following directoryList's order), you can chain ./ or ../ after */ to get to the file you want:

//custom/foo.js
import * as bar from '*/../path/to/bar';

Options

• directoryList [Array] (required) :Two or more absolute paths where your files are located, sorted by priority. Example: ["path/to/dir-1", "path/to/dir-2", ..., "path/to/dir-n", "path/to/source-dir"]

• excludePath [RegEx] (defaults to "node_modules"): RegEx which matches the path property of the request object which should not be resolved (i.e. the path leading to the file you're requiring or importing).

• excludeRequest [RegEx] (defaults to "node_modules"): RegEx which matches the request property of the request object which should not be resolved (i.e. what you type in a require or import statement: "./foo" ).

• fileExtension [String] (defaults to ".js"): Extension name to append to files that lack an explicit type. Note: When requiring or importing a directory, this plugin will resort to default Webpack behavior, which is to look for an "/index.{extension}" file inside of said directory.

• nextDirectoryPrefix [String] (defaults to "*/"): Specify a pattern to match at the beginning of an import request. You only need to change this in case of using another plugin that looks for the default pattern.