Handle assignments in document exported

This improves detection of cases where we have:

```js
export const f = function () {};
export const o = { ... };
```

and similarly indirection using default/named.

```js
const f = function () {};
export {f};
```

Fixes documentationjs#543

Author: arv

lib/extractors/exported.js

@@ -3,7 +3,8 @@ var traverse = require('babel-traverse').default,
   t = require('babel-types'),
   nodePath = require('path'),
   fs = require('fs'),
-  parseToAst = require('../parsers/parse_to_ast');
+  parseToAst = require('../parsers/parse_to_ast'),
+  findTarget = require('../infer/finders').findTarget;
 
 /**
  * Iterate through the abstract syntax tree, finding ES6-style exports,
@@ -52,14 +53,18 @@ function walkExported(ast, data, addComment) {
       var declaration = path.get('declaration');
       if (t.isDeclaration(declaration)) {
         traverseExportedSubtree(declaration, data, addComments);
+        return path.skip();
       }
 
       if (path.isExportDefaultDeclaration()) {
         if (declaration.isDeclaration()) {
           traverseExportedSubtree(declaration, data, addComments);
-        } else if (declaration.isIdentifier()) {
+          return path.skip();
+        }
+        if (declaration.isIdentifier()) {
           var binding = declaration.scope.getBinding(declaration.node.name);
           traverseExportedSubtree(binding.path, data, addComments);
+          return path.skip();
         }
       }
 
@@ -92,6 +97,7 @@ function walkExported(ast, data, addComment) {
 
           traverseExportedSubtree(bindingPath, specData, addComments, exported);
         });
+        return path.skip();
       }
     }
   });
@@ -110,12 +116,10 @@ function traverseExportedSubtree(path, data, addComments, overrideName) {
   }
   addComments(data, attachCommentPath, overrideName);
 
-  if (path.isVariableDeclaration()) {
-    // TODO: How does JSDoc handle multiple declarations?
-    path = path.get('declarations')[0].get('init');
-    if (!path) {
-      return;
-    }
+  path = findTarget(path);
+
+  if (t.isVariableDeclarator(path) && path.has('init')) {
+    path = path.get('init');
   }
 
   if (path.isClass() || path.isObjectExpression()) {

lib/infer/augments.js

@@ -1,7 +1,7 @@
 'use strict';
 
 var shouldSkipInference = require('./should_skip_inference'),
-  finders = require('./finders');
+  findClass = require('./finders').findClass;
 
 /**
  * Infers an `augments` tag from an ES6 class declaration
@@ -15,12 +15,12 @@ function inferAugments() {
       return comment;
     }
 
-    var node = finders.findClass(comment.context.ast);
+    var path = findClass(comment.context.ast);
 
-    if (node && node.superClass) {
+    if (path && path.node.superClass) {
       comment.augments = [{
         title: 'augments',
-        name: node.superClass.name
+        name: path.node.superClass.name
       }];
     }
 

lib/infer/finders.js

@@ -1,51 +1,50 @@
+'use strict';
+
 var t = require('babel-types');
 
 /**
  * Try to find the part of JavaScript a comment is referring to, by
  * looking at the syntax tree closest to that comment.
  *
  * @param {Object} path abstract syntax tree path
- * @returns {?Object} ast node, if one is found.
+ * @returns {?Object} ast path, if one is found.
  * @private
  */
 function findTarget(path) {
-
   if (!path) {
     return path;
   }
 
-  if (path.node) {
-    path = path.node;
-  }
-
-  if (t.isExportNamedDeclaration(path) || t.isExportDefaultDeclaration(path)) {
-    path = path.declaration;
+  if (t.isExportDefaultDeclaration(path) ||
+    t.isExportNamedDeclaration(path) && path.has('declaration')) {
+    path = path.get('declaration');
   }
 
   // var x = init;
   if (t.isVariableDeclaration(path)) {
-    return path.declarations[0];
-  }
+    path = path.get('declarations')[0];
 
   // foo.x = TARGET
-  if (t.isExpressionStatement(path)) {
-    return path.expression.right;
+  } else if (t.isExpressionStatement(path)) {
+    path = path.get('expression').get('right');
   }
 
-  return path;
+  return path.node && path;
 }
 
 /**
  * Try to find a JavaScript class that this comment refers to,
  * whether an expression in an assignment, or a declaration.
  *
- * @param {Object} node abstract syntax tree node
- * @returns {?Object} ast node, if one is found.
+ * @param {Object} path abstract syntax tree path
+ * @returns {?Object} ast path, if one is found.
  * @private
  */
-function findClass(node) {
-  var target = findTarget(node);
-  return (t.isClassDeclaration(target) || t.isClassExpression(target)) && target;
+function findClass(path) {
+  var target = findTarget(path);
+  if (target && (target.isClassDeclaration() || target.isClassExpression())) {
+    return target;
+  }
 }
 
 module.exports.findTarget = findTarget;

lib/infer/params.js

@@ -2,7 +2,7 @@
 
 var shouldSkipInference = require('./should_skip_inference'),
   t = require('babel-types'),
-  finders = require('./finders'),
+  findTarget = require('./finders').findTarget,
   flowDoctrine = require('../flow_doctrine');
 
 /**
@@ -160,15 +160,15 @@ function paramToDoc(param, comment, i, prefix) {
  */
 function inferParams() {
   return shouldSkipInference(function inferParams(comment) {
-    var node = finders.findTarget(comment.context.ast);
+    var path = findTarget(comment.context.ast);
 
     // In case of `/** */ var x = function () {}` findTarget returns
     // the declarator.
-    if (t.isVariableDeclarator(node)) {
-      node = node.init;
+    if (t.isVariableDeclarator(path)) {
+      path = path.get('init');
     }
 
-    if (!t.isFunction(node)) {
+    if (!t.isFunction(path)) {
       return comment;
     }
 
@@ -182,7 +182,7 @@ function inferParams() {
     var paramOrder = {};
     var i = 0;
 
-    node.params
+    path.node.params
       .reduce(function (params, param, i) {
         return params.concat(paramToDoc(param, comment, i));
       }, [])

lib/infer/return.js

@@ -17,7 +17,8 @@ module.exports = function () {
     if (comment.returns) {
       return comment;
     }
-    var fn = finders.findTarget(comment.context.ast);
+    var path = finders.findTarget(comment.context.ast);
+    var fn = path && path.node;
     if (t.isFunction(fn) &&
       fn.returnType &&
       fn.returnType.typeAnnotation) {

lib/infer/type.js

@@ -1,6 +1,6 @@
 'use strict';
 
-var finders = require('./finders'),
+var findTarget = require('./finders').findTarget,
   shouldSkipInference = require('./should_skip_inference'),
   flowDoctrine = require('../flow_doctrine'),
   t = require('babel-types');
@@ -24,11 +24,12 @@ module.exports = function () {
       return comment;
     }
 
-    var n = finders.findTarget(comment.context.ast);
-    if (!n) {
+    var path = findTarget(comment.context.ast);
+    if (!path) {
       return comment;
     }
 
+    var n = path.node;
     var type;
     switch (n.type) {
     case 'VariableDeclarator':

test/fixture/document-exported.input.js

@@ -63,3 +63,17 @@ type T3 = string;
 export type {T2, T3 as T4};
 
 export type {T5} from './document-exported/x.js';
+
+export var f4 = function(x: X) {}
+
+var f5 = function(y: Y) {}
+export {f5};
+
+export var o1 = {
+  om1() {}
+}
+
+var o2 = {
+  om2() {}
+}
+export {o2};