From 56e80ad1a39d0d1e878db9fd9a8fd737559814dc Mon Sep 17 00:00:00 2001
From: Neo <nihgwu@live.com>
Date: Tue, 9 Apr 2019 16:25:12 +0800
Subject: [PATCH] fix typo and update doc

---
 docs/docs/browser-support.md                  |  6 +--
 .../src/utils/__tests__/webpack.config.js     | 39 ++++++++-----------
 packages/gatsby/src/utils/webpack.config.js   | 12 +++---
 3 files changed, 25 insertions(+), 32 deletions(-)

diff --git a/docs/docs/browser-support.md b/docs/docs/browser-support.md
index 76035882921f6..3186b0f582a2c 100644
--- a/docs/docs/browser-support.md
+++ b/docs/docs/browser-support.md
@@ -49,8 +49,6 @@ By default, Gatsby emulates the following config:
 If you only support newer browsers, make sure to specify this in your
 `package.json`. This will often enable you to ship smaller JavaScript files.
 
-## Note about IE < 11
+## Note about IE support
 
-React depends on collection types `Map` and `Set`. While these are not used by Gatsby, Gatsby uses React and you will need to polyfill these if you support older browsers and devices including IE < 11.
-
-Read more about this in [https://reactjs.org/docs/javascript-environment-requirements.html](https://reactjs.org/docs/javascript-environment-requirements.html)
+Gatsby will polyfil minimum requirements for IE support according to the `browserslist` config.
diff --git a/packages/gatsby/src/utils/__tests__/webpack.config.js b/packages/gatsby/src/utils/__tests__/webpack.config.js
index fb9f9ce146163..bbe7f97627a4b 100644
--- a/packages/gatsby/src/utils/__tests__/webpack.config.js
+++ b/packages/gatsby/src/utils/__tests__/webpack.config.js
@@ -17,6 +17,7 @@ const { DefinePlugin } = require(`webpack`)
 const { readFileSync } = require(`fs-extra`)
 const webpackConfig = require(`../webpack.config`)
 const { store } = require(`../../redux`)
+const { joinPath } = require(`../path`)
 
 beforeEach(() => {
   DefinePlugin.mockClear()
@@ -119,53 +120,47 @@ describe(`environment variables`, () => {
   })
 })
 
-describe(`polyfil for ie support`, () => {
-  it(`should not add ie polyfil if ie is not supported`, async () => {
+describe(`polyfill for ie support`, () => {
+  const directory = `gatsby-app`
+  const appEntry = joinPath(directory, `.cache/production-app`)
+
+  it(`should not add ie polyfill if ie is not supported`, async () => {
     const config = await getConfig(
       { browserslist: `defaults, not ie >= 9` },
-      `gatsby-app`,
+      directory,
       `build-javascript`
     )
 
-    expect(config.entry.app).toEqual([`gatsby-app/.cache/production-app`])
+    expect(config.entry.app).toEqual([appEntry])
   })
 
-  it(`should add ie9 polyfil if ie >= 9 is supported`, async () => {
+  it(`should add ie9 polyfill if ie >= 9 is supported`, async () => {
     const config = await getConfig(
       { browserslist: `defaults, ie >= 9` },
-      `gatsby-app`,
+      directory,
       `build-javascript`
     )
 
-    expect(config.entry.app).toEqual([
-      `react-app-polyfill/ie9`,
-      `gatsby-app/.cache/production-app`,
-    ])
+    expect(config.entry.app).toEqual([`react-app-polyfill/ie9`, appEntry])
   })
 
-  it(`should add ie9 polyfil if ie >= 10 is supported`, async () => {
+  it(`should add ie9 polyfill if ie >= 10 is supported`, async () => {
     const config = await getConfig(
       { browserslist: `defaults, ie >= 10` },
-      `gatsby-app`,
+      directory,
       `build-javascript`
     )
 
-    expect(config.entry.app).toEqual([
-      `react-app-polyfill/ie9`,
-      `gatsby-app/.cache/production-app`,
-    ])
+    expect(config.entry.app).toEqual([`react-app-polyfill/ie9`, appEntry])
   })
 
-  it(`should add ie11 polyfil if ie >= 11 is supported`, async () => {
+  it(`should add ie11 polyfill if ie >= 11 is supported`, async () => {
     const config = await getConfig(
       { browserslist: `defaults, ie >= 11` },
-      `gatsby-app`,
+      directory,
       `build-javascript`
     )
 
-    expect(config.entry.app).toEqual([
-      `react-app-polyfill/ie11`,
-      `gatsby-app/.cache/production-app`,
-    ])
+    expect(config.entry.app).toEqual([`react-app-polyfill/ie11`, appEntry])
   })
 })
diff --git a/packages/gatsby/src/utils/webpack.config.js b/packages/gatsby/src/utils/webpack.config.js
index 636b5d1d96c87..d568be73d11c2 100644
--- a/packages/gatsby/src/utils/webpack.config.js
+++ b/packages/gatsby/src/utils/webpack.config.js
@@ -30,16 +30,16 @@ module.exports = async (
 ) => {
   const directoryPath = withBasePath(directory)
 
-  // Polyfil for IE support
+  // Polyfill for IE support
   const supportedBrowsers = browserslist(program.browserslist)
-  let iePolyfil = false
+  let iePolyfill = false
   if (
     supportedBrowsers.includes(`ie 9`) ||
     supportedBrowsers.includes(`ie 10`)
   ) {
-    iePolyfil = `react-app-polyfill/ie9`
+    iePolyfill = `react-app-polyfill/ie9`
   } else if (supportedBrowsers.includes(`ie 11`)) {
-    iePolyfil = `react-app-polyfill/ie11`
+    iePolyfill = `react-app-polyfill/ie11`
   }
 
   process.env.GATSBY_BUILD_STAGE = suppliedStage
@@ -164,7 +164,7 @@ module.exports = async (
       case `develop`:
         return {
           commons: [
-            iePolyfil,
+            iePolyfill,
             `event-source-polyfill`,
             `${require.resolve(
               `webpack-hot-middleware/client`
@@ -182,7 +182,7 @@ module.exports = async (
         }
       case `build-javascript`:
         return {
-          app: [iePolyfil, directoryPath(`.cache/production-app`)].filter(
+          app: [iePolyfill, directoryPath(`.cache/production-app`)].filter(
             Boolean
           ),
         }