Move .inherits handling to OptionManager.

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

@@ -7,6 +7,8 @@ import merge from "./helpers/merge";
 import removed from "./removed";
 import buildConfigChain from "./build-config-chain";
 import path from "path";
+import traverse from "babel-traverse";
+import clone from "lodash/clone";
 
 import { loadPlugin, loadPreset, loadParser, loadGenerator } from "./loading/files";
 
@@ -74,6 +76,15 @@ const optionNames = new Set([
   "generatorOpts",
 ]);
 
+const ALLOWED_PLUGIN_KEYS = new Set([
+  "name",
+  "manipulateOptions",
+  "pre",
+  "post",
+  "visitor",
+  "inherits",
+]);
+
 export default class OptionManager {
   constructor() {
     this.options = OptionManager.createBareOptions();
@@ -99,16 +110,51 @@ export default class OptionManager {
       obj = fn;
     }
 
-    if (typeof obj === "object") {
-      const plugin = new Plugin(obj, alias);
-      OptionManager.memoisedPlugins.push({
-        container: fn,
-        plugin: plugin,
-      });
-      return plugin;
-    } else {
+    if (typeof obj !== "object") {
       throw new TypeError(messages.get("pluginNotObject", loc, i, typeof obj) + loc + i);
     }
+    Object.keys(obj).forEach((key) => {
+      if (!ALLOWED_PLUGIN_KEYS.has(key)) {
+        throw new Error(messages.get("pluginInvalidProperty", loc, i, key));
+      }
+    });
+    if (obj.visitor && (obj.visitor.enter || obj.visitor.exit)) {
+      throw new Error("Plugins aren't allowed to specify catch-all enter/exit handlers. " +
+        "Please target individual nodes.");
+    }
+
+    obj = Object.assign({}, obj, {
+      visitor: clone(obj.visitor || {}),
+    });
+
+    traverse.explode(obj.visitor);
+
+    if (obj.inherits) {
+      const inherited = OptionManager.normalisePlugin(obj.inherits, loc, "inherits");
+
+      obj.pre = OptionManager.chain(inherited.pre, obj.pre);
+      obj.post = OptionManager.chain(inherited.post, obj.post);
+      obj.manipulateOptions = OptionManager.chain(inherited.manipulateOptions, obj.manipulateOptions);
+      obj.visitor = traverse.visitors.merge([inherited.visitor, obj.visitor]);
+    }
+
+    const plugin = new Plugin(obj, alias);
+    OptionManager.memoisedPlugins.push({
+      container: fn,
+      plugin: plugin,
+    });
+    return plugin;
+  }
+
+  static chain(a, b) {
+    const fns = [a, b].filter(Boolean);
+    if (fns.length <= 1) return fns[0];
+
+    return function(...args) {
+      for (const fn of fns) {
+        fn.apply(this, args);
+      }
+    };
   }
 
   static createBareOptions() {
@@ -137,8 +183,6 @@ export default class OptionManager {
       }
     }
 
-    plugin.init(loc, i);
-
     return plugin;
   }
 

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

@@ -1,90 +1,16 @@
-import OptionManager from "./option-manager";
-import * as messages from "babel-messages";
-import traverse from "babel-traverse";
-import clone from "lodash/clone";
-
-const GLOBAL_VISITOR_PROPS = ["enter", "exit"];
-
 export default class Plugin {
   constructor(plugin: Object, key?: string) {
-    this.initialized = false;
-    this.raw = Object.assign({}, plugin);
-    this.key = this.take("name") || key;
+    this.key = plugin.name || key;
 
-    this.manipulateOptions = this.take("manipulateOptions");
-    this.post = this.take("post");
-    this.pre = this.take("pre");
-    this.visitor = this.normaliseVisitor(clone(this.take("visitor")) || {});
+    this.manipulateOptions = plugin.manipulateOptions;
+    this.post = plugin.post;
+    this.pre = plugin.pre;
+    this.visitor = plugin.visitor;
   }
 
-  initialized: boolean;
-  raw: Object;
+  key: ?string;
   manipulateOptions: ?Function;
   post: ?Function;
   pre: ?Function;
   visitor: Object;
-
-  take(key) {
-    const val = this.raw[key];
-    delete this.raw[key];
-    return val;
-  }
-
-  chain(target, key) {
-    if (!target[key]) return this[key];
-    if (!this[key]) return target[key];
-
-    const fns: Array<?Function> = [target[key], this[key]];
-
-    return function (...args) {
-      let val;
-      for (const fn of fns) {
-        if (fn) {
-          const ret = fn.apply(this, args);
-          if (ret != null) val = ret;
-        }
-      }
-      return val;
-    };
-  }
-
-  maybeInherit(loc: string) {
-    let inherits = this.take("inherits");
-    if (!inherits) return;
-
-    inherits = OptionManager.normalisePlugin(inherits, loc, "inherits");
-
-    this.manipulateOptions = this.chain(inherits, "manipulateOptions");
-    this.post = this.chain(inherits, "post");
-    this.pre = this.chain(inherits, "pre");
-    this.visitor = traverse.visitors.merge([inherits.visitor, this.visitor]);
-  }
-
-  /**
-   * We lazy initialise parts of a plugin that rely on contextual information such as
-   * position on disk and how it was specified.
-   */
-
-  init(loc: string, i: number) {
-    if (this.initialized) return;
-    this.initialized = true;
-
-    this.maybeInherit(loc);
-
-    for (const key in this.raw) {
-      throw new Error(messages.get("pluginInvalidProperty", loc, i, key));
-    }
-  }
-
-  normaliseVisitor(visitor: Object): Object {
-    for (const key of GLOBAL_VISITOR_PROPS) {
-      if (visitor[key]) {
-        throw new Error("Plugins aren't allowed to specify catch-all enter/exit handlers. " +
-          "Please target individual nodes.");
-      }
-    }
-
-    traverse.explode(visitor);
-    return visitor;
-  }
 }