feat: add additionalData option (#248)

README.md

@@ -45,11 +45,12 @@ And run `webpack` via your preferred method.
 
 ## Options
 
-|                   Name                    |         Type         |      Default       | Description                                    |
-| :---------------------------------------: | :------------------: | :----------------: | :--------------------------------------------- |
-|   **[`stylusOptions`](#stylusOptions)**   | `{Object\|Function}` |        `{}`        | Options for Stylus.                            |
-|       **[`sourceMap`](#sourcemap)**       |     `{Boolean}`      | `compiler.devtool` | Enables/Disables generation of source maps.    |
-| **[`webpackImporter`](#webpackimporter)** |     `{Boolean}`      |       `true`       | Enables/Disables the default Webpack importer. |
+|                   Name                    |         Type         |      Default       | Description                                              |
+| :---------------------------------------: | :------------------: | :----------------: | :------------------------------------------------------- |
+|   **[`stylusOptions`](#stylusOptions)**   | `{Object\|Function}` |        `{}`        | Options for Stylus.                                      |
+|       **[`sourceMap`](#sourcemap)**       |     `{Boolean}`      | `compiler.devtool` | Enables/Disables generation of source maps.              |
+| **[`webpackImporter`](#webpackimporter)** |     `{Boolean}`      |       `true`       | Enables/Disables the default Webpack importer.           |
+|  **[`additionalData`](#additionalData)**  | `{String\|Function}` |    `undefined`     | Prepends/Appends `Stylus` code to the actual entry file. |
 
 ### `stylusOptions`
 
@@ -210,6 +211,76 @@ module.exports = {
 };
 ```
 
+### `additionalData`
+
+Type: `String|Function`
+Default: `undefined`
+
+Prepends `Stylus` code before the actual entry file.
+In this case, the `stylus-loader` will not override the source but just **prepend** the entry's content.
+
+This is especially useful when some of your Stylus variables depend on the environment:
+
+> ℹ Since you're injecting code, this will break the source mappings in your entry file. Often there's a simpler solution than this, like multiple Stylus entry files.
+
+#### `String`
+
+```js
+module.exports = {
+  module: {
+    rules: [
+      {
+        test: /\.styl/,
+        use: [
+          'style-loader',
+          'css-loader',
+          {
+            loader: 'stylus-loader',
+            options: {
+              additionalData: `@env: ${process.env.NODE_ENV};`,
+            },
+          },
+        ],
+      },
+    ],
+  },
+};
+```
+
+#### `Function`
+
+```js
+module.exports = {
+  module: {
+    rules: [
+      {
+        test: /\.styl/,
+        use: [
+          'style-loader',
+          'css-loader',
+          {
+            loader: 'stylus-loader',
+            options: {
+              additionalData: (content, loaderContext) => {
+                // More information about available properties https://webpack.js.org/api/loaders/
+                const { resourcePath, rootContext } = loaderContext;
+                const relativePath = path.relative(rootContext, resourcePath);
+
+                if (relativePath === 'styles/foo.styl') {
+                  return 'value = 100px' + content;
+                }
+
+                return 'value 200px' + content;
+              },
+            },
+          },
+        ],
+      },
+    ],
+  },
+};
+```
+
 ## Examples
 
 ### Normal usage

src/index.js

@@ -33,7 +33,16 @@ export default async function stylusLoader(source) {
     };
   }
 
-  const styl = stylus(source, stylusOptions);
+  let data = source;
+
+  if (typeof options.additionalData !== 'undefined') {
+    data =
+      typeof options.additionalData === 'function'
+        ? `${options.additionalData(data, this)}`
+        : `${options.additionalData}\n${data}`;
+  }
+
+  const styl = stylus(data, stylusOptions);
 
   if (typeof stylusOptions.include !== 'undefined') {
     for (const included of stylusOptions.include) {

src/options.json

@@ -20,6 +20,17 @@
     "webpackImporter": {
       "description": "Enables/Disables default `webpack` importer (https://github.com/webpack-contrib/stylus-loader#webpackimporter).",
       "type": "boolean"
+    },
+    "additionalData": {
+      "description": "Prepends/Appends `Stylus` code to the actual entry file (https://github.com/webpack-contrib/stylus-loader#additionalData).",
+      "anyOf": [
+        {
+          "type": "string"
+        },
+        {
+          "instanceof": "Function"
+        }
+      ]
     }
   },
   "additionalProperties": false

test/__snapshots__/additionalData-option.test.js.snap

@@ -0,0 +1,27 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`"additionalData" option should work additionalData data as function: css 1`] = `
+"/* RelativePath: additional-data.styl; */
+body {
+  color: #ff7f50;
+}
+.custom-class {
+  background: #808080;
+}
+"
+`;
+
+exports[`"additionalData" option should work additionalData data as function: errors 1`] = `Array []`;
+
+exports[`"additionalData" option should work additionalData data as function: warnings 1`] = `Array []`;
+
+exports[`"additionalData" option should work additionalData data as string: css 1`] = `
+"body {
+  color: #ff7f50;
+}
+"
+`;
+
+exports[`"additionalData" option should work additionalData data as string: errors 1`] = `Array []`;
+
+exports[`"additionalData" option should work additionalData data as string: warnings 1`] = `Array []`;

test/__snapshots__/validate-options.test.js.snap

@@ -1,5 +1,65 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
+exports[`validate options should throw an error on the "additionalData" option with "/test/" value 1`] = `
+"Invalid options object. Stylus Loader has been initialized using an options object that does not match the API schema.
+ - options.additionalData should be one of these:
+   string | function
+   -> Prepends/Appends \`Stylus\` code to the actual entry file (https://github.com/webpack-contrib/stylus-loader#additionalData).
+   Details:
+    * options.additionalData should be a string.
+    * options.additionalData should be an instance of function."
+`;
+
+exports[`validate options should throw an error on the "additionalData" option with "[]" value 1`] = `
+"Invalid options object. Stylus Loader has been initialized using an options object that does not match the API schema.
+ - options.additionalData should be one of these:
+   string | function
+   -> Prepends/Appends \`Stylus\` code to the actual entry file (https://github.com/webpack-contrib/stylus-loader#additionalData).
+   Details:
+    * options.additionalData should be a string.
+    * options.additionalData should be an instance of function."
+`;
+
+exports[`validate options should throw an error on the "additionalData" option with "{}" value 1`] = `
+"Invalid options object. Stylus Loader has been initialized using an options object that does not match the API schema.
+ - options.additionalData should be one of these:
+   string | function
+   -> Prepends/Appends \`Stylus\` code to the actual entry file (https://github.com/webpack-contrib/stylus-loader#additionalData).
+   Details:
+    * options.additionalData should be a string.
+    * options.additionalData should be an instance of function."
+`;
+
+exports[`validate options should throw an error on the "additionalData" option with "1" value 1`] = `
+"Invalid options object. Stylus Loader has been initialized using an options object that does not match the API schema.
+ - options.additionalData should be one of these:
+   string | function
+   -> Prepends/Appends \`Stylus\` code to the actual entry file (https://github.com/webpack-contrib/stylus-loader#additionalData).
+   Details:
+    * options.additionalData should be a string.
+    * options.additionalData should be an instance of function."
+`;
+
+exports[`validate options should throw an error on the "additionalData" option with "false" value 1`] = `
+"Invalid options object. Stylus Loader has been initialized using an options object that does not match the API schema.
+ - options.additionalData should be one of these:
+   string | function
+   -> Prepends/Appends \`Stylus\` code to the actual entry file (https://github.com/webpack-contrib/stylus-loader#additionalData).
+   Details:
+    * options.additionalData should be a string.
+    * options.additionalData should be an instance of function."
+`;
+
+exports[`validate options should throw an error on the "additionalData" option with "true" value 1`] = `
+"Invalid options object. Stylus Loader has been initialized using an options object that does not match the API schema.
+ - options.additionalData should be one of these:
+   string | function
+   -> Prepends/Appends \`Stylus\` code to the actual entry file (https://github.com/webpack-contrib/stylus-loader#additionalData).
+   Details:
+    * options.additionalData should be a string.
+    * options.additionalData should be an instance of function."
+`;
+
 exports[`validate options should throw an error on the "sourceMap" option with "string" value 1`] = `
 "Invalid options object. Stylus Loader has been initialized using an options object that does not match the API schema.
  - options.sourceMap should be a boolean.
@@ -64,49 +124,49 @@ exports[`validate options should throw an error on the "stylusOptions" option wi
 exports[`validate options should throw an error on the "unknown" option with "/test/" value 1`] = `
 "Invalid options object. Stylus Loader has been initialized using an options object that does not match the API schema.
  - options has an unknown property 'unknown'. These properties are valid:
-   object { stylusOptions?, sourceMap?, webpackImporter? }"
+   object { stylusOptions?, sourceMap?, webpackImporter?, additionalData? }"
 `;
 
 exports[`validate options should throw an error on the "unknown" option with "[]" value 1`] = `
 "Invalid options object. Stylus Loader has been initialized using an options object that does not match the API schema.
  - options has an unknown property 'unknown'. These properties are valid:
-   object { stylusOptions?, sourceMap?, webpackImporter? }"
+   object { stylusOptions?, sourceMap?, webpackImporter?, additionalData? }"
 `;
 
 exports[`validate options should throw an error on the "unknown" option with "{"foo":"bar"}" value 1`] = `
 "Invalid options object. Stylus Loader has been initialized using an options object that does not match the API schema.
  - options has an unknown property 'unknown'. These properties are valid:
-   object { stylusOptions?, sourceMap?, webpackImporter? }"
+   object { stylusOptions?, sourceMap?, webpackImporter?, additionalData? }"
 `;
 
 exports[`validate options should throw an error on the "unknown" option with "{}" value 1`] = `
 "Invalid options object. Stylus Loader has been initialized using an options object that does not match the API schema.
  - options has an unknown property 'unknown'. These properties are valid:
-   object { stylusOptions?, sourceMap?, webpackImporter? }"
+   object { stylusOptions?, sourceMap?, webpackImporter?, additionalData? }"
 `;
 
 exports[`validate options should throw an error on the "unknown" option with "1" value 1`] = `
 "Invalid options object. Stylus Loader has been initialized using an options object that does not match the API schema.
  - options has an unknown property 'unknown'. These properties are valid:
-   object { stylusOptions?, sourceMap?, webpackImporter? }"
+   object { stylusOptions?, sourceMap?, webpackImporter?, additionalData? }"
 `;
 
 exports[`validate options should throw an error on the "unknown" option with "false" value 1`] = `
 "Invalid options object. Stylus Loader has been initialized using an options object that does not match the API schema.
  - options has an unknown property 'unknown'. These properties are valid:
-   object { stylusOptions?, sourceMap?, webpackImporter? }"
+   object { stylusOptions?, sourceMap?, webpackImporter?, additionalData? }"
 `;
 
 exports[`validate options should throw an error on the "unknown" option with "test" value 1`] = `
 "Invalid options object. Stylus Loader has been initialized using an options object that does not match the API schema.
  - options has an unknown property 'unknown'. These properties are valid:
-   object { stylusOptions?, sourceMap?, webpackImporter? }"
+   object { stylusOptions?, sourceMap?, webpackImporter?, additionalData? }"
 `;
 
 exports[`validate options should throw an error on the "unknown" option with "true" value 1`] = `
 "Invalid options object. Stylus Loader has been initialized using an options object that does not match the API schema.
  - options has an unknown property 'unknown'. These properties are valid:
-   object { stylusOptions?, sourceMap?, webpackImporter? }"
+   object { stylusOptions?, sourceMap?, webpackImporter?, additionalData? }"
 `;
 
 exports[`validate options should throw an error on the "webpackImporter" option with "string" value 1`] = `

test/additionalData-option.test.js

@@ -0,0 +1,49 @@
+import {
+  compile,
+  getCodeFromBundle,
+  getCompiler,
+  getErrors,
+  getWarnings,
+} from './helpers';
+
+describe('"additionalData" option', () => {
+  it('should work additionalData data as string', async () => {
+    const testId = './additional-data.styl';
+    const additionalData = 'color = coral';
+    const compiler = getCompiler(testId, { additionalData });
+    const stats = await compile(compiler);
+    const codeFromBundle = getCodeFromBundle(stats, compiler);
+
+    expect(codeFromBundle.css).toMatchSnapshot('css');
+    expect(getWarnings(stats)).toMatchSnapshot('warnings');
+    expect(getErrors(stats)).toMatchSnapshot('errors');
+  });
+
+  it('should work additionalData data as function', async () => {
+    const testId = './additional-data.styl';
+    const additionalData = (content, loaderContext) => {
+      const { resourcePath, rootContext } = loaderContext;
+      // eslint-disable-next-line global-require
+      const relativePath = require('path').relative(rootContext, resourcePath);
+
+      return `
+/* RelativePath: ${relativePath}; */
+
+color = coral;
+bg = gray;
+
+${content}
+
+.custom-class
+  background: bg
+        `;
+    };
+    const compiler = getCompiler(testId, { additionalData });
+    const stats = await compile(compiler);
+    const codeFromBundle = getCodeFromBundle(stats, compiler);
+
+    expect(codeFromBundle.css).toMatchSnapshot('css');
+    expect(getWarnings(stats)).toMatchSnapshot('warnings');
+    expect(getErrors(stats)).toMatchSnapshot('errors');
+  });
+});

test/fixtures/additional-data.styl

@@ -0,0 +1,2 @@
+body
+  color color

test/validate-options.test.js

@@ -34,6 +34,10 @@ describe('validate options', () => {
       success: [true, false],
       failure: ['string'],
     },
+    additionalData: {
+      success: ['color = coral', () => 'bg = coral'],
+      failure: [1, true, false, /test/, [], {}],
+    },
     unknown: {
       success: [],
       failure: [1, true, false, 'test', /test/, [], {}, { foo: 'bar' }],