From 0aa0495aedc235a5392ea81b97e31b8db2ab8056 Mon Sep 17 00:00:00 2001
From: Mike Allanson <michael.allanson@gmail.com>
Date: Fri, 16 Mar 2018 15:44:34 -0700
Subject: [PATCH] Detect additional export syntaxes

---
 .../__tests__/resolve-module-exports.js       | 12 ++++++++++
 .../src/bootstrap/resolve-module-exports.js   | 22 ++++++++++++++++---
 2 files changed, 31 insertions(+), 3 deletions(-)

diff --git a/packages/gatsby/src/bootstrap/__tests__/resolve-module-exports.js b/packages/gatsby/src/bootstrap/__tests__/resolve-module-exports.js
index 3090e5f7316eb..50381a4358bab 100644
--- a/packages/gatsby/src/bootstrap/__tests__/resolve-module-exports.js
+++ b/packages/gatsby/src/bootstrap/__tests__/resolve-module-exports.js
@@ -7,6 +7,8 @@ describe(`Resolve module exports`, () => {
   const MOCK_FILE_INFO = {
     "/bad/file": `const exports.blah = () = }}}`,
     "/simple/export": `exports.foo = '';`,
+    "/export/const": `export const fooConst = '';`,
+    "/module/exports": `module.exports.barExports = '';`,
     "/multiple/export": `exports.bar = () => ''; exports.baz = {}; exports.foo = '';`,
     "/import/with/export": `import React from 'react'; exports.baz = '';`,
     "/realistic/export": `
@@ -136,6 +138,16 @@ describe(`Resolve module exports`, () => {
     expect(result).toEqual([`baz`])
   })
 
+  it(`Resolves an exported const`, () => {
+    const result = resolveModuleExports(`/export/const`, resolver)
+    expect(result).toEqual([`fooConst`])
+  })
+
+  it(`Resolves module.exports`, () => {
+    const result = resolveModuleExports(`/module/exports`, resolver)
+    expect(result).toEqual([`barExports`])
+  })
+
   it(`Resolves exports from a larger file`, () => {
     const result = resolveModuleExports(`/realistic/export`, resolver)
     expect(result).toEqual([`replaceHistory`, `replaceComponentRenderer`])
diff --git a/packages/gatsby/src/bootstrap/resolve-module-exports.js b/packages/gatsby/src/bootstrap/resolve-module-exports.js
index 744263bd891fc..59c9f77ce5bda 100644
--- a/packages/gatsby/src/bootstrap/resolve-module-exports.js
+++ b/packages/gatsby/src/bootstrap/resolve-module-exports.js
@@ -2,6 +2,7 @@
 const fs = require(`fs`)
 const babylon = require(`babylon`)
 const traverse = require(`babel-traverse`).default
+const get = require(`lodash/get`)
 
 /**
  * Given a `require.resolve()` compatible path pointing to a JS module,
@@ -45,12 +46,27 @@ module.exports = (modulePath, resolver = require.resolve) => {
 
   // extract names of exports from file
   traverse(ast, {
+    // get foo from `export const foo = bar`
+    ExportNamedDeclaration: function ExportNamedDeclaration(astPath) {
+      const exportName = get(astPath, `node.declaration.declarations[0].id.name`)
+      if (exportName) exportNames.push(exportName)
+    },
     AssignmentExpression: function AssignmentExpression(astPath) {
+      const nodeLeft = astPath.node.left
+
+      if (nodeLeft.type !== `MemberExpression`) return
+
+      // get foo from `exports.foo = bar`
+      if (get(nodeLeft, `object.name`) === `exports`) {
+        exportNames.push(nodeLeft.property.name)
+      }
+
+      // get foo from `module.exports.foo = bar`
       if (
-        astPath.node.left.type === `MemberExpression` &&
-        astPath.node.left.object.name === `exports`
+        get(nodeLeft, `object.object.name`) === `module` &&
+        get(nodeLeft, `object.property.name`) === `exports`
       ) {
-        exportNames.push(astPath.node.left.property.name)
+        exportNames.push(nodeLeft.property.name)
       }
     },
   })