Make displayNameHandler take displayName getter into account

Now the display name will correctly be picked up for a component defined
as

```
class Component extends React.Component {
  static get displayName() {
    return 'Name';
  }
}
```

Fixes #61

Author: fkling

src/__tests__/__snapshots__/main-test.js.snap

@@ -5,3 +5,38 @@ Object {
   "methods": Array []
 }
 `;
+
+exports[`main fixtures processes component "component_2.js" without errors 1`] = `
+Object {
+  "description": "",
+  "displayName": "button",
+  "methods": Array [
+    Object {
+      "docblock": null,
+      "modifiers": Array [
+        "static"
+      ],
+      "name": "displayName",
+      "params": Array [],
+      "returns": null
+    },
+    Object {
+      "docblock": null,
+      "modifiers": Array [
+        "static"
+      ],
+      "name": "defaultProps",
+      "params": Array [],
+      "returns": null
+    }
+  ],
+  "props": Object {
+    "type": Object {
+      "defaultValue": Object {
+        "computed": false,
+        "value": "\"primary\""
+      }
+    }
+  }
+}
+`;

src/__tests__/fixtures/component_1.js

@@ -1,3 +1,13 @@
+/*
+ *  Copyright (c) 2015, Facebook, Inc.
+ *  All rights reserved.
+ *
+ *  This source code is licensed under the BSD-style license found in the
+ *  LICENSE file in the root directory of this source tree. An additional grant
+ *  of patent rights can be found in the PATENTS file in the same directory.
+ *
+ */
+
 var Component, React;
 
 React = require('react');

src/__tests__/fixtures/component_2.js

@@ -0,0 +1,23 @@
+/*
+ *  Copyright (c) 2015, Facebook, Inc.
+ *  All rights reserved.
+ *
+ *  This source code is licensed under the BSD-style license found in the
+ *  LICENSE file in the root directory of this source tree. An additional grant
+ *  of patent rights can be found in the PATENTS file in the same directory.
+ *
+ */
+
+import React from 'react';
+
+export class Button extends React.Component {
+  static get displayName() {
+    return "button";
+  }
+
+  static get defaultProps() {
+    return {
+      type: "primary",
+    };
+  }
+}

src/handlers/__tests__/displayNameHandler-test.js

@@ -70,17 +70,33 @@ describe('defaultPropsHandler', () => {
     expect(documentation.displayName).not.toBeDefined();
   });
 
-  it('ignores non-literal names', () => {
-    var definition = expression('({displayName: foo.bar})');
-    expect(() => displayNameHandler(documentation, definition)).not.toThrow();
-    expect(documentation.displayName).not.toBeDefined();
+  describe('ClassDeclaration displayName getter', () => {
+
+    it('considers class methods', () => {
+      const definition = statement(`
+        class Foo {
+          static get displayName() {
+            return 'foo';
+          }
+        }
+      `);
+      expect(() => displayNameHandler(documentation, definition)).not.toThrow();
+      expect(documentation.displayName).toBe('foo');
+    });
+
+    it('resolves variables in class methods', () => {
+      const definition = statement(`
+        class Foo {
+          static get displayName() {
+            return abc;
+          }
+        }
+        const abc = 'bar';
+      `);
+      expect(() => displayNameHandler(documentation, definition)).not.toThrow();
+      expect(documentation.displayName).toBe('bar');
+    });
 
-    definition = statement(`
-      class Foo {
-        static displayName = foo.bar;
-      }
-    `);
-    expect(() => displayNameHandler(documentation, definition)).not.toThrow();
-    expect(documentation.displayName).not.toBeDefined();
   });
+
 });

src/handlers/displayNameHandler.js

@@ -15,18 +15,31 @@ import type Documentation from '../Documentation';
 import getMemberValuePath from '../utils/getMemberValuePath';
 import recast from 'recast';
 import resolveToValue from '../utils/resolveToValue';
+import {traverseShallow} from '../utils/traverse';
 
-var {types: {namedTypes: types}} = recast;
+const {types: {namedTypes: types}} = recast;
 
 export default function displayNameHandler(
   documentation: Documentation,
   path: NodePath
 ) {
-  var displayNamePath = getMemberValuePath(path, 'displayName');
+  let displayNamePath = getMemberValuePath(path, 'displayName');
   if (!displayNamePath) {
     return;
   }
   displayNamePath = resolveToValue(displayNamePath);
+
+  // If display name is defined as a getter we get a function expression as
+  // value. In that case we try to determine the value from the return
+  // statement.
+  if (types.FunctionExpression.check(displayNamePath.node)) {
+    traverseShallow(displayNamePath.get('body'), {
+      visitReturnStatement: path => {
+        displayNamePath = resolveToValue(path.get('argument'));
+        return false;
+      },
+    });
+  }
   if (!displayNamePath || !types.Literal.check(displayNamePath.node)) {
     return;
   }

src/utils/__tests__/getClassMemberValuePath-test.js

@@ -55,6 +55,29 @@ describe('getClassMemberValuePath', () => {
     });
   });
 
+  describe('Getters and Setters', () => {
+    it('finds getters', () => {
+      var def = statement(`
+        class Foo {
+          get foo() {}
+        }
+      `);
+
+      expect(getClassMemberValuePath(def, 'foo'))
+        .toBe(def.get('body', 'body', 0, 'value'));
+    });
+
+    it('ignores setters', () => {
+      var def = statement(`
+        class Foo {
+          set foo(val) {}
+        }
+      `);
+
+      expect(getClassMemberValuePath(def, 'foo')).not.toBeDefined();
+    });
+  });
+
   describe('ClassProperty', () => {
     it('finds "normal" class properties', () => {
       var def = statement(`

src/utils/getClassMemberValuePath.js

@@ -25,7 +25,8 @@ export default function getClassMemberValuePath(
   return classDefinition.get('body', 'body')
     .filter(memberPath => (
       (!memberPath.node.computed || types.Literal.check(memberPath.node.key)) &&
-      getNameOrValue(memberPath.get('key')) === memberName
+      getNameOrValue(memberPath.get('key')) === memberName &&
+      memberPath.node.kind !== 'set'
     ))
     .map(memberPath => memberPath.get('value'))[0];
 }