Rewrite Hub as interface #5047 (#5050)

* Rewrite Hub as interface #5047

* Update index.js

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

@@ -6,7 +6,8 @@ import convertSourceMap from "convert-source-map";
 import OptionManager from "./options/option-manager";
 import type Pipeline from "../pipeline";
 import PluginPass from "../plugin-pass";
-import { NodePath, Hub, Scope } from "babel-traverse";
+import { NodePath, Scope } from "babel-traverse";
+import type { HubInterface } from "babel-traverse";
 import sourceMap from "source-map";
 import generate from "babel-generator";
 import codeFrame from "babel-code-frame";
@@ -98,7 +99,21 @@ export default class File extends Store {
     this.code    = "";
     this.shebang = "";
 
-    this.hub = new Hub(this);
+    this.hub = {
+      // keep it for the usage in babel-core, ex: path.hub.file.opts.filename
+      file: this,
+      mark: (type: string, message: string, loc: Object) => {
+        this.metadata.marked.push({
+          type,
+          message,
+          loc
+        });
+      },
+      addHelper: this.addHelper.bind(this),
+      getCode: () => this.code,
+      getScope: () => this.scope,
+      buildError: this.buildCodeFrameError.bind(this)
+    };
   }
 
   static helpers: Array<string>;
@@ -118,7 +133,7 @@ export default class File extends Store {
   ast: Object;
   scope: Scope;
   metadata: BabelFileMetadata;
-  hub: Hub;
+  hub: HubInterface;
   code: string;
   shebang: string;
 

packages/babel-traverse/src/hub.js

@@ -1,6 +1,14 @@
+import Scope from "./scope";
+export interface HubInterface {
+  mark?: (type: string, message: string) => void;
+  addHelper?: (name: string) => Object;
+  getScope?: () => Scope;
+  getCode?: () => string;
+  buildError:(node: Object, msg: string, Error: Error) => Error;
+}
+
 export default class Hub {
-  constructor(file, options) {
-    this.file = file;
-    this.options = options;
+  buildError(node, msg, BuildError = TypeError): Error {
+    return new BuildError(msg);
   }
 }

packages/babel-traverse/src/index.js

@@ -5,10 +5,12 @@ import includes from "lodash/includes";
 import * as t from "babel-types";
 import * as cache from "./cache";
 
-export { default as NodePath } from "./path";
-export { default as Scope } from "./scope";
-export { default as Hub } from "./hub";
-export { visitors };
+import NodePath from "./path";
+import Scope from "./scope";
+import Hub from "./hub";
+
+export { visitors, NodePath, Scope, Hub };
+export type { HubInterface } from "./hub";
 
 export default function traverse(
   parent: Object | Array<Object>,
@@ -35,9 +37,9 @@ traverse.visitors = visitors;
 traverse.verify = visitors.verify;
 traverse.explode = visitors.explode;
 
-traverse.NodePath = require("./path");
-traverse.Scope    = require("./scope");
-traverse.Hub      = require("./hub");
+traverse.NodePath = NodePath;
+traverse.Scope    = Scope;
+traverse.Hub      = Hub;
 
 traverse.cheap = function (node, enter) {
   return t.traverseFast(node, enter);

packages/babel-traverse/src/path/index.js

@@ -114,19 +114,17 @@ export default class NodePath {
   }
 
   buildCodeFrameError(msg: string, Error: typeof Error = SyntaxError): Error {
-    return this.hub.file.buildCodeFrameError(this.node, msg, Error);
+    return this.hub.buildError(this.node, msg, Error);
   }
 
   traverse(visitor: Object, state?: any) {
     traverse(this.node, visitor, this.scope, state, this);
   }
 
   mark(type: string, message: string) {
-    this.hub.file.metadata.marked.push({
-      type,
-      message,
-      loc: this.node.loc
-    });
+    if (this.hub.mark) {
+      this.hub.mark(type, message, this.node.loc);
+    }
   }
 
   set(key: string, node: Object) {

packages/babel-traverse/src/path/introspection.js

@@ -235,10 +235,12 @@ export function referencesImport(moduleSource, importName) {
 export function getSource() {
   const node = this.node;
   if (node.end) {
-    return this.hub.file.code.slice(node.start, node.end);
-  } else {
-    return "";
+    const code = this.hub.getCode();
+    if (code) {
+      return code.slice(node.start, node.end);
+    }
   }
+  return "";
 }
 
 export function willIMaybeExecuteBefore(target) {

packages/babel-traverse/src/scope/index.js

@@ -346,7 +346,8 @@ export default class Scope {
       local.kind === "param" && (kind === "let" || kind === "const");
 
     if (duplicate) {
-      throw this.hub.file.buildCodeFrameError(id, messages.get("scopeDuplicateDeclaration", name), TypeError);
+      const errorMsg = messages.get("scopeDuplicateDeclaration", name);
+      throw this.hub.buildError ? this.hub.buildError(id, errorMsg, TypeError) : new TypeError(errorMsg);
     }
   }
 
@@ -385,8 +386,6 @@ export default class Scope {
   }
 
   toArray(node: Object, i?: number) {
-    const file = this.hub.file;
-
     if (t.isIdentifier(node)) {
       const binding = this.getBinding(node.name);
       if (binding && binding.constant && binding.path.isGenericType("Array")) return node;
@@ -419,9 +418,9 @@ export default class Scope {
     } else if (i) {
       args.push(t.numericLiteral(i));
       helperName = "slicedToArray";
-      // TODO if (this.hub.file.isLoose("es6.forOf")) helperName += "-loose";
+      // TODO if (this.hub.isLoose("es6.forOf")) helperName += "-loose";
     }
-    return t.callExpression(file.addHelper(helperName), args);
+    return t.callExpression(this.hub.addHelper(helperName), args);
   }
 
   hasLabel(name: string) {

packages/babel-traverse/test/hub.js

@@ -0,0 +1,13 @@
+const assert = require("assert");
+const Hub = require("../lib").default.Hub;
+
+describe("hub", function () {
+  it("default buildError should return TypeError", function () {
+    const hub = new Hub();
+    const msg = "test_msg";
+    assert.deepEqual(
+      hub.buildError(null, msg),
+      new TypeError(msg)
+    );
+  });
+});