fix: improve require es module

Compile such as babel, typescript will compile es module always
containing `__esModule`, we should do right things.

Typescript 2.2 fix this bug in
microsoft/TypeScript#13871

Author: popomore

lib/loader/mixin/extend.js

@@ -1,7 +1,6 @@
 'use strict';
 
 const path = require('path');
-const interopRequire = require('interop-require');
 const debug = require('debug')('egg-core:extend');
 const utils = require('../../utils');
 
@@ -85,13 +84,7 @@ module.exports = {
         continue;
       }
 
-      let ext;
-      try {
-        ext = interopRequire(filepath);
-      } catch (err) {
-        err.message = `[egg-core] load file ${require.resolve(filepath)} error: ${err.message}`;
-        throw err;
-      }
+      const ext = utils.loadFile(filepath);
 
       const properties = Object.getOwnPropertyNames(ext)
         .concat(Object.getOwnPropertySymbols(ext));

lib/utils/index.js

@@ -2,22 +2,23 @@
 
 const co = require('co');
 const path = require('path');
-const interopRequire = require('interop-require');
 const homedir = require('node-homedir');
 const is = require('is-type-of');
 
 
 module.exports = {
 
   loadFile(filepath) {
-    let exports;
     try {
-      exports = interopRequire(filepath);
+      const obj = require(filepath);
+      if (!obj) return obj;
+      // it's es module
+      if (obj.__esModule) return 'default' in obj ? obj.default : obj;
+      return obj;
     } catch (err) {
-      err.message = 'load file: ' + filepath + ', error: ' + err.message;
+      err.message = '[egg-core] load file: ' + filepath + ', error: ' + err.message;
       throw err;
     }
-    return exports;
   },
 
   existsModule(filepath) {

package.json

@@ -33,33 +33,32 @@
   },
   "devDependencies": {
     "autod": "^2.7.1",
-    "egg-bin": "^2.0.2",
+    "egg-bin": "^2.2.1",
     "egg-ci": "^1.1.0",
-    "eslint": "^3.15.0",
+    "eslint": "^3.16.1",
     "eslint-config-egg": "^3.2.0",
     "mm": "^2.1.0",
     "mz-modules": "^1.0.0",
     "pedding": "^1.1.0",
-    "rimraf": "^2.5.4",
+    "rimraf": "^2.6.0",
     "spy": "^1.0.0",
     "supertest": "^3.0.0"
   },
   "dependencies": {
     "co": "^4.6.0",
-    "debug": "^2.6.0",
+    "debug": "^2.6.1",
     "depd": "^1.1.0",
     "egg-logger": "^1.5.0",
     "egg-path-matching": "^1.0.0",
     "extend": "^3.0.0",
     "globby": "^6.1.0",
     "inflection": "^1.12.0",
-    "interop-require": "^1.0.0",
     "is-type-of": "^1.0.0",
-    "koa": "^1.2.4",
+    "koa": "^1.2.5",
     "koa-router": "^5.4.0",
     "node-homedir": "^1.0.0",
-    "ready-callback": "^2.0.0",
-    "utility": "^1.9.0"
+    "ready-callback": "^2.0.1",
+    "utility": "^1.11.0"
   },
   "files": [
     "lib",

test/fixtures/loadfile/es-module-default-null.js

@@ -0,0 +1,3 @@
+"use strict";
+exports.__esModule = true;
+exports["default"] = null;

test/fixtures/loadfile/es-module-default.js

@@ -0,0 +1,5 @@
+"use strict";
+exports.__esModule = true;
+exports["default"] = {
+  fn() {}
+};

test/fixtures/loadfile/es-module.js

@@ -0,0 +1,6 @@
+"use strict";
+exports.__esModule = true;
+function fn() {
+    console.log(fn);
+}
+exports.fn = fn;

test/fixtures/loadfile/null.js

@@ -0,0 +1,3 @@
+'use strict';
+
+module.exports = null;

test/fixtures/loadfile/object.js

@@ -0,0 +1,3 @@
+'use strict';
+
+module.exports = { a: 1 };

test/fixtures/loadfile/zero.js

@@ -0,0 +1,3 @@
+'use strict';
+
+module.exports = 0;

test/utils/index.test.js

@@ -2,6 +2,7 @@
 
 const mm = require('mm');
 const os = require('os');
+const path = require('path');
 const assert = require('assert');
 const sleep = require('mz-modules/sleep');
 const utils = require('../../lib/utils');
@@ -71,4 +72,37 @@ describe('test/utils/index.test.js', () => {
       assert.deepEqual(result, [ 1, 2 ]);
     });
   });
+
+  describe('loadFile', () => {
+    const baseDir = path.join(__dirname, '../fixtures/loadfile');
+    it('should load object', () => {
+      const result = utils.loadFile(path.join(baseDir, 'object.js'));
+      assert(result.a === 1);
+    });
+
+    it('should load null', () => {
+      const result = utils.loadFile(path.join(baseDir, 'null.js'));
+      assert(result === null);
+    });
+
+    it('should load null', () => {
+      const result = utils.loadFile(path.join(baseDir, 'zero.js'));
+      assert(result === 0);
+    });
+
+    it('should load es module', () => {
+      const result = utils.loadFile(path.join(baseDir, 'es-module.js'));
+      assert(result.fn);
+    });
+
+    it('should load es module with default', () => {
+      const result = utils.loadFile(path.join(baseDir, 'es-module-default.js'));
+      assert(result.fn);
+    });
+
+    it('should load es module with default = null', () => {
+      const result = utils.loadFile(path.join(baseDir, 'es-module-default-null.js'));
+      assert(result === null);
+    });
+  });
 });