Allow macro config to come from plugin options in babel config.

other/docs/author.md

@@ -4,9 +4,9 @@
 
 Is this your first time working with ASTs? Here are some resources:
 
-* [Writing custom Babel and ESLint plugins with ASTs](https://youtu.be/VBscbcm2Mok?list=PLV5CVI1eNcJgNqzNwcs4UKrlJdhfDjshf): A 53 minute talk by [@kentcdodds](https://twitter.com/kentcdodds)
-* [babel-handbook](https://github.com/thejameskyle/babel-handbook): A guided handbook on how to use Babel and how to create plugins for Babel by [@thejameskyle](https://twitter.com/thejameskyle)
-* [Code Transformation and Linting](https://kentcdodds.com/workshops/#code-transformation-and-linting): A workshop (recording available on Frontend Masters) with exercises of making custom Babel and ESLint plugins
+- [Writing custom Babel and ESLint plugins with ASTs](https://youtu.be/VBscbcm2Mok?list=PLV5CVI1eNcJgNqzNwcs4UKrlJdhfDjshf): A 53 minute talk by [@kentcdodds](https://twitter.com/kentcdodds)
+- [babel-handbook](https://github.com/thejameskyle/babel-handbook): A guided handbook on how to use Babel and how to create plugins for Babel by [@thejameskyle](https://twitter.com/thejameskyle)
+- [Code Transformation and Linting](https://kentcdodds.com/workshops/#code-transformation-and-linting): A workshop (recording available on Frontend Masters) with exercises of making custom Babel and ESLint plugins
 
 ## Writing a macro
 
@@ -164,43 +164,53 @@ This is a string used as import declaration's source - i.e. `'./my.macro'`.
 
 #### config (EXPERIMENTAL!)
 
-There is an experimental feature that allows users to configure your macro. We
-use [`cosmiconfig`][cosmiconfig] to read a `babel-plugin-macros` configuration which
+There is an experimental feature that allows users to configure your macro.
+
+To specify that your plugin is configurable, you pass a `configName` to `createMacro`.
+
+A configuration is created from data combined from two sources:
+We use [`cosmiconfig`][cosmiconfig] to read a `babel-plugin-macros` configuration which
 can be located in any of the following files up the directories from the
 importing file:
 
-* `.babel-plugin-macrosrc`
-* `.babel-plugin-macrosrc.json`
-* `.babel-plugin-macrosrc.yaml`
-* `.babel-plugin-macrosrc.yml`
-* `.babel-plugin-macrosrc.js`
-* `babel-plugin-macros.config.js`
-* `babelMacros` in `package.json`
+- `.babel-plugin-macrosrc`
+- `.babel-plugin-macrosrc.json`
+- `.babel-plugin-macrosrc.yaml`
+- `.babel-plugin-macrosrc.yml`
+- `.babel-plugin-macrosrc.js`
+- `babel-plugin-macros.config.js`
+- `babelMacros` in `package.json`
 
-To specify that your plugin is configurable, you pass a `configName` to
-`createMacro`:
+The content of the config will be merged with the content of the babel macros plugin
+options. Plugin options take priority.
+
+All together specifying and using the config might look like this:
 
 ```javascript
-const {createMacro} = require('babel-plugin-macros')
-const configName = 'taggedTranslations'
-module.exports = createMacro(taggedTranslationsMacro, {configName})
-function taggedTranslationsMacro({references, state, babel, config}) {
-  // config would be taggedTranslations portion of the config as loaded from `cosmiconfig`
+// .babel-plugin-macros.config.js
+module.exports = {
+  taggedTranslations: { locale: 'en_US' }
 }
-```
 
-Then to configure this, users would do something like this:
-
-```javascript
-// babel-plugin-macros.config.js
+// .babel.config.js
 module.exports = {
-  taggedTranslations: {
-    someConfig: {},
-  },
+  plugins: [
+    ['macros': {
+      taggedTranslations: { locale: 'en_GB' }
+    }]
+  ]
+}
+
+// taggedTranslations.macro.js
+const {createMacro} = require('babel-plugin-macros')
+module.exports = createMacro(taggedTranslationsMacro, {configName: 'taggedTranslations'})
+function taggedTranslationsMacro({references, state, babel, config}) {
+  const { locale = 'en' } = config;
 }
 ```
 
-And the `config` object you would receive would be: `{someConfig: {}}`.
+Note that in the above example if both files were sepcified the finale locale value would
+be `en_GB`, since that is the value in the plugin options.
 
 ### Keeping imports
 

src/index.js

@@ -48,7 +48,7 @@ function nodeResolvePath(source, basedir) {
 
 function macrosPlugin(
   babel,
-  {require: _require = require, resolvePath = nodeResolvePath} = {},
+  {require: _require = require, resolvePath = nodeResolvePath, ...options} = {},
 ) {
   function interopRequire(path) {
     // eslint-disable-next-line import/no-dynamic-require
@@ -88,6 +88,7 @@ function macrosPlugin(
               babel,
               interopRequire,
               resolvePath,
+              options,
             })
 
             if (!result || !result.keepImports) {
@@ -152,6 +153,7 @@ function applyMacros({
   babel,
   interopRequire,
   resolvePath,
+  options,
 }) {
   /* istanbul ignore next (pretty much only useful for astexplorer I think) */
   const {
@@ -183,7 +185,7 @@ function applyMacros({
         `Please refer to the documentation to see how to do this properly: https://github.com/kentcdodds/babel-plugin-macros/blob/master/other/docs/author.md#writing-a-macro`,
     )
   }
-  const config = getConfig(macro, filename, source)
+  const config = getConfig(macro, filename, source, options)
 
   let result
   try {
@@ -228,9 +230,20 @@ function applyMacros({
   return result
 }
 
-// eslint-disable-next-line consistent-return
-function getConfig(macro, filename, source) {
-  if (macro.options.configName) {
+function getConfig(macro, filename, source, options) {
+  const {configName} = macro.options
+  if (configName) {
+    let callOptions, configOptions, configError, configPath
+
+    if (Object.prototype.hasOwnProperty.call(options, configName)) {
+      if (configName && !typeof options[configName] === 'object') {
+        throw new Error(
+          `The macro plugin options' ${configName} property was not an object or null.`,
+        )
+      }
+      callOptions = options[configName]
+    }
+
     try {
       // lazy-loading it here to avoid perf issues of loading it up front.
       // No I did not measure. Yes I'm a bad person.
@@ -240,32 +253,55 @@ function getConfig(macro, filename, source) {
       const explorer = require('cosmiconfig')('babel-plugin-macros', {
         searchPlaces: [
           'package.json',
-          `.babel-plugin-macrosrc`,
-          `.babel-plugin-macrosrc.json`,
-          `.babel-plugin-macrosrc.yaml`,
-          `.babel-plugin-macrosrc.yml`,
-          `.babel-plugin-macrosrc.js`,
-          `babel-plugin-macros.config.js`,
+          '.babel-plugin-macrosrc',
+          '.babel-plugin-macrosrc.json',
+          '.babel-plugin-macrosrc.yaml',
+          '.babel-plugin-macrosrc.yml',
+          '.babel-plugin-macrosrc.js',
+          'babel-plugin-macros.config.js',
         ],
         packageProp: 'babelMacros',
         sync: true,
       })
       const loaded = explorer.searchSync(filename)
       if (loaded) {
-        return loaded.config[macro.options.configName]
+        configOptions = loaded.config[configName]
+        configPath = loaded.filepath
       }
-    } catch (error) {
+    } catch (e) {
+      configError = e
+    }
+
+    if (callOptions === undefined && configOptions === undefined) {
       // eslint-disable-next-line no-console
       console.error(
-        `There was an error trying to load the config "${
-          macro.options.configName
-        }" ` +
+        `There was an error trying to load the config "${configName}" ` +
           `for the macro imported from "${source}. ` +
           `Please see the error thrown for more information.`,
       )
-      throw error
+      if (configError !== undefined) {
+        throw configError
+      }
+    }
+
+    if (
+      configOptions &&
+      callOptions !== undefined &&
+      typeof callOptions !== 'object'
+    ) {
+      throw new Error(
+        `${configPath} specified a ${configName} config of type ${typeof configOptions}, `,
+        `but the the macros plugin's options.${configName} did contain an object.`,
+        `Both configs must contain objects for their options to be mergeable.`,
+      )
+    }
+
+    return {
+      ...configOptions,
+      ...callOptions,
     }
   }
+  return undefined
 }
 
 /*