Track options on the plugin instance to avoid array pair usage.

packages/babel-core/src/config/index.js

@@ -9,7 +9,7 @@ export type ResolvedConfig = {
 };
 
 export type { Plugin };
-export type PluginPassList = Array<[Plugin, ?{}]>;
+export type PluginPassList = Array<Plugin>;
 export type PluginPasses = Array<PluginPassList>;
 
 /**

packages/babel-core/src/config/option-manager.js

@@ -79,7 +79,7 @@ const ALLOWED_PLUGIN_KEYS = new Set([
 
 export default function manageOptions(opts: {}): {
   options: Object,
-  passes: Array<Array<[Plugin, ?{}]>>,
+  passes: Array<Array<Plugin>>,
 } | null {
   return new OptionManager().init(opts);
 }
@@ -91,7 +91,7 @@ class OptionManager {
   }
 
   options: Object;
-  passes: Array<Array<[Plugin, ?{}]>>;
+  passes: Array<Array<Plugin>>;
 
   /**
    * This is called when we want to merge the input `opts` into the
@@ -102,7 +102,7 @@ class OptionManager {
    *  - `dirname` is used to resolve plugins relative to it.
    */
 
-  mergeOptions(config: MergeOptions, pass?: Array<[Plugin, ?{}]>) {
+  mergeOptions(config: MergeOptions, pass?: Array<Plugin>) {
     const result = loadConfig(config);
 
     const plugins = result.plugins.map(descriptor =>
@@ -315,12 +315,16 @@ const loadDescriptor = makeWeakCache((descriptor, cache) => {
  */
 function loadPluginDescriptor(descriptor: BasicDescriptor) {
   if (descriptor.value instanceof Plugin) {
-    return [descriptor.value, descriptor.options];
+    if (descriptor.options) {
+      throw new Error(
+        "Passed options to an existing Plugin instance will not work.",
+      );
+    }
+
+    return descriptor.value;
   }
 
-  const result = instantiatePlugin(loadDescriptor(descriptor));
-
-  return [result, descriptor.options];
+  return instantiatePlugin(loadDescriptor(descriptor));
 }
 
 const instantiatePlugin = makeWeakCache(
@@ -360,8 +364,8 @@ const instantiatePlugin = makeWeakCache(
       };
 
       // If the inherited plugin changes, reinstantiate this plugin.
-      inherits = cache.invalidate(
-        () => loadPluginDescriptor(inheritsDescriptor)[0],
+      inherits = cache.invalidate(() =>
+        loadPluginDescriptor(inheritsDescriptor),
       );
 
       plugin.pre = chain(inherits.pre, plugin.pre);
@@ -376,7 +380,7 @@ const instantiatePlugin = makeWeakCache(
       ]);
     }
 
-    return new Plugin(plugin, descriptor.alias);
+    return new Plugin(plugin, descriptor.options, descriptor.alias);
   },
 );
 

packages/babel-core/src/config/plugin.js

@@ -7,7 +7,9 @@ export default class Plugin {
   pre: ?Function;
   visitor: ?{};
 
-  constructor(plugin: {}, key?: string) {
+  options: {} | void;
+
+  constructor(plugin: {}, options: ?{}, key?: string) {
     if (plugin.name != null && typeof plugin.name !== "string") {
       throw new Error("Plugin .name must be a string, null, or undefined");
     }
@@ -35,5 +37,6 @@ export default class Plugin {
     this.post = plugin.post;
     this.pre = plugin.pre;
     this.visitor = plugin.visitor;
+    this.options = options || undefined;
   }
 }

packages/babel-core/src/transformation/block-hoist-plugin.js

@@ -6,7 +6,7 @@ import loadConfig, { type Plugin } from "../config";
 
 let LOADED_PLUGIN: Plugin | void;
 
-export default function loadBlockHoistPlugin(): [Plugin, void] {
+export default function loadBlockHoistPlugin(): Plugin {
   if (!LOADED_PLUGIN) {
     // Lazy-init the internal plugin to remove the init-time circular
     // dependency between plugins being passed babel-core's export object,
@@ -15,11 +15,11 @@ export default function loadBlockHoistPlugin(): [Plugin, void] {
       babelrc: false,
       plugins: [blockHoistPlugin],
     });
-    LOADED_PLUGIN = config ? config.passes[0][0][0] : undefined;
+    LOADED_PLUGIN = config ? config.passes[0][0] : undefined;
     if (!LOADED_PLUGIN) throw new Error("Assertion failure");
   }
 
-  return [LOADED_PLUGIN, undefined];
+  return LOADED_PLUGIN;
 }
 
 const blockHoistPlugin = {

packages/babel-core/src/transformation/index.js

@@ -49,10 +49,8 @@ function transformFile(file: File, pluginPasses: PluginPasses): void {
     const passes = [];
     const visitors = [];
 
-    for (const [plugin, pluginOpts] of pluginPairs.concat([
-      loadBlockHoistPlugin(),
-    ])) {
-      const pass = new PluginPass(file, plugin.key, pluginOpts);
+    for (const plugin of pluginPairs.concat([loadBlockHoistPlugin()])) {
+      const pass = new PluginPass(file, plugin.key, plugin.options);
 
       passPairs.push([plugin, pass]);
       passes.push(pass);

packages/babel-core/src/transformation/normalize-opts.js

@@ -15,7 +15,7 @@ export default function normalizeOptions(config: ResolvedConfig): {} {
   });
 
   for (const pluginPairs of config.passes) {
-    for (const [plugin] of pluginPairs) {
+    for (const plugin of pluginPairs) {
       if (plugin.manipulateOptions) {
         plugin.manipulateOptions(options, options.parserOpts);
       }

packages/babel-core/test/api.js

@@ -154,9 +154,8 @@ describe("api", function() {
       plugins: [__dirname + "/../../babel-plugin-syntax-jsx"],
     }).then(function(result) {
       assert.ok(
-        result.options.plugins[0][0].manipulateOptions
-          .toString()
-          .indexOf("jsx") >= 0,
+        result.options.plugins[0].manipulateOptions.toString().indexOf("jsx") >=
+          0,
       );
     });
   });