move eslint out of the core into a separate plugin

src/babel/api/node.js

@@ -2,13 +2,13 @@ import isFunction from "lodash/lang/isFunction";
 import transform from "../transformation";
 import fs from "fs";
 
+export { default as acorn } from "acorn-babel";
 export { default as _util, canCompile } from "../util";
 export { default as transform } from "../transformation";
-
-export { version } from "../../../package";
-
+export { default as traverse } from "../traversal";
 export { default as buildExternalHelpers } from "../build-external-helpers";
 export { default as types } from "../types";
+export { version } from "../../../package";
 
 export function register(opts) {
   var callback = require("./register/node");

src/babel/generation/index.js

@@ -11,7 +11,9 @@ import n from "./node";
 import t from "../types";
 
 class CodeGenerator {
-  constructor(ast, opts = {}, code) {
+  constructor(ast, opts, code) {
+    opts ||= {};
+
     this.comments = ast.comments || [];
     this.tokens   = ast.tokens || [];
     this.format   = CodeGenerator.normalizeOptions(code, opts);

src/babel/helpers/acorn-to-esprima.js

@@ -1,49 +0,0 @@
-import traverse from "../traversal";
-import { tokTypes } from "acorn-babel";
-import t from "../types";
-
-export function toEsprimaToken(token) {
-  var type = token.type;
-
-  if (type === tokTypes.name) {
-    token.type = "Identifier";
-  } else if (type === tokTypes.semi || type === tokTypes.comma || type === tokTypes.parenL || type === tokTypes.parenR || type === tokTypes.braceL || type === tokTypes.braceR) {
-    token.type = "Punctuator";
-    token.value = type.type;
-  }
-
-  return token;
-}
-
-export function toEsprimaAST(ast) {
-  traverse(ast, astTransformVisitor);
-}
-
-var astTransformVisitor = {
-  noScope: true,
-  enter(node) {
-    if (t.isImportBatchSpecifier(node)) {
-      node.type = "ImportNamespaceSpecifier";
-      node.id = node.name;
-      delete node.name;
-    } else if (t.isFunction(node)) {
-      node.defaults = [];
-
-      node.params = node.params.map(function (param) {
-        if (t.isAssignmentPattern(param)) {
-          node.defaults.push(param.right);
-          return param.left;
-        } else {
-          node.defaults.push(null);
-          return param;
-        }
-      });
-
-      if (t.isRestElement(node.params[node.params.length - 1])) {
-        node.rest = node.params.pop();
-      }
-    } else if (t.isClassProperty(node)) {
-      this.remove();
-    }
-  }
-};