Feat: Add updateProps config option (#868)

Author: ryanoglesby08

docs/Configuration.md

@@ -43,6 +43,7 @@ By default, Styleguidist will look for `styleguide.config.js` file in your proje
 * [`title`](#title)
 * [`transformProps`](#transformprops)
 * [`updateExample`](#updateexample)
+* [`updateProps`](#updateprops)
 * [`verbose`](#verbose)
 * [`webpackConfig`](#webpackconfig)
 
@@ -554,6 +555,45 @@ module.exports = {
 }
 ```
 
+#### `updateProps`
+
+Type: `Function`, optional
+
+Function that modifies props after parsing from a source file. For example you can use it to load a component version from a package.json file:
+
+```javascript
+module.exports = {
+  updateProps: function(props) {
+    if (props.doclets.version) {
+      const versionFilePath = path.resolve(
+        path.dirname(file),
+        props.doclets.version
+      )
+      const version = require(versionFilePath).version
+
+      props.doclets.version = version
+      props.tags.version[0].description = version
+    }
+
+    return props
+  }
+}
+```
+
+With this component JSDoc comment block:
+
+```javascript
+/**
+ * Component is described here.
+ *
+ * @version ./package.json
+ */
+export default class Button extends React.Component {
+  // ...
+}
+export default
+```
+
 #### `verbose`
 
 Type: `Boolean`, default: `false`

loaders/__tests__/props-loader.spec.js

@@ -205,9 +205,7 @@ it('should add context dependencies to webpack from contextDependencies config o
 	const result = propsLoader.call(
 		{
 			request: file,
-			_styleguidist: Object.assign(_styleguidist, {
-				contextDependencies,
-			}),
+			_styleguidist: { ..._styleguidist, contextDependencies },
 			addContextDependency,
 		},
 		readFileSync(file, 'utf8')
@@ -218,3 +216,21 @@ it('should add context dependencies to webpack from contextDependencies config o
 	expect(addContextDependency).toBeCalledWith(contextDependencies[0]);
 	expect(addContextDependency).toBeCalledWith(contextDependencies[1]);
 });
+
+it('should update the returned props object after enhancing from the updateProps config option', () => {
+	const updateProps = jest.fn();
+	const file = './test/components/Button/Button.js';
+	const result = propsLoader.call(
+		{
+			request: file,
+			_styleguidist: { ..._styleguidist, updateProps },
+		},
+		readFileSync(file, 'utf8')
+	);
+
+	expect(() => new vm.Script(result)).not.toThrow();
+	expect(updateProps).toHaveBeenCalledWith(
+		expect.objectContaining({ displayName: 'Button' }),
+		'./test/components/Button/Button.js'
+	);
+});

loaders/props-loader.js

@@ -72,6 +72,10 @@ module.exports = function(source) {
 	const examplesFile = config.getExampleFilename(file);
 	props.examples = getExamples(examplesFile, props.displayName, config.defaultExample);
 
+	if (config.updateProps) {
+		props = config.updateProps(props, file);
+	}
+
 	return `
 if (module.hot) {
 	module.hot.accept([])

scripts/schemas/config.js

@@ -268,6 +268,9 @@ module.exports = {
 			return props;
 		},
 	},
+	updateProps: {
+		type: 'function',
+	},
 	updateWebpackConfig: {
 		type: 'function',
 		removed: `Use "webpackConfig" option instead:\n${consts.DOCS_WEBPACK}`,