From 0878685a5a8f1916fbe95e4277d3d2d57ce7d06b Mon Sep 17 00:00:00 2001
From: Joshua Peek <josh@joshpeek.com>
Date: Mon, 1 Feb 2016 17:03:13 -0800
Subject: [PATCH 1/3] Defer requiring chokidar dependency until --watch flag is
 passed

---
 packages/babel-cli/src/babel/dir.js  | 3 ++-
 packages/babel-cli/src/babel/file.js | 2 +-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/packages/babel-cli/src/babel/dir.js b/packages/babel-cli/src/babel/dir.js
index c2a34b7711..4e4cb11c1d 100644
--- a/packages/babel-cli/src/babel/dir.js
+++ b/packages/babel-cli/src/babel/dir.js
@@ -1,6 +1,5 @@
 let outputFileSync = require("output-file-sync");
 let pathExists     = require("path-exists");
-let chokidar       = require("chokidar");
 let slash          = require("slash");
 let path           = require("path");
 let util           = require("./util");
@@ -65,6 +64,8 @@ module.exports = function (commander, filenames) {
   _.each(filenames, handle);
 
   if (commander.watch) {
+    let chokidar = require("chokidar");
+
     _.each(filenames, function (dirname) {
       let watcher = chokidar.watch(dirname, {
         persistent: true,
diff --git a/packages/babel-cli/src/babel/file.js b/packages/babel-cli/src/babel/file.js
index 01ec93c711..9ab05ed696 100644
--- a/packages/babel-cli/src/babel/file.js
+++ b/packages/babel-cli/src/babel/file.js
@@ -1,7 +1,6 @@
 let convertSourceMap = require("convert-source-map");
 let pathExists       = require("path-exists");
 let sourceMap        = require("source-map");
-let chokidar         = require("chokidar");
 let slash            = require("slash");
 let path             = require("path");
 let util             = require("./util");
@@ -133,6 +132,7 @@ module.exports = function (commander, filenames, opts) {
     walk();
 
     if (commander.watch) {
+      let chokidar = require("chokidar");
       chokidar.watch(filenames, {
         persistent: true,
         ignoreInitial: true

From f81d9e1274ffeb8b558603e74d771e6f84a9b0d5 Mon Sep 17 00:00:00 2001
From: Joshua Peek <josh@joshpeek.com>
Date: Mon, 1 Feb 2016 17:03:37 -0800
Subject: [PATCH 2/3] Mark chokidar as optional dependency

---
 packages/babel-cli/package.json | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/packages/babel-cli/package.json b/packages/babel-cli/package.json
index 108c351cf4..20e62a05fd 100644
--- a/packages/babel-cli/package.json
+++ b/packages/babel-cli/package.json
@@ -13,7 +13,6 @@
     "babel-runtime": "^5.0.0",
     "bin-version-check": "^2.1.0",
     "chalk": "1.1.1",
-    "chokidar": "^1.0.0",
     "commander": "^2.8.1",
     "convert-source-map": "^1.1.0",
     "fs-readdir-recursive": "^0.1.0",
@@ -28,6 +27,9 @@
     "source-map": "^0.5.0",
     "v8flags": "^2.0.10"
   },
+  "optionalDependencies": {
+    "chokidar": "^1.0.0"
+  },
   "devDependencies": {
     "babel-helper-fixtures": "^6.3.13"
   },

From 005c4cb7a867d2c9a55309d0f43052d879fbcc48 Mon Sep 17 00:00:00 2001
From: Joshua Peek <josh@joshpeek.com>
Date: Mon, 1 Feb 2016 19:24:08 -0800
Subject: [PATCH 3/3] Show specific error message when chokidar can't be loaded

---
 packages/babel-cli/src/babel/dir.js  | 2 +-
 packages/babel-cli/src/babel/file.js | 2 +-
 packages/babel-cli/src/babel/util.js | 9 +++++++++
 3 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/packages/babel-cli/src/babel/dir.js b/packages/babel-cli/src/babel/dir.js
index 4e4cb11c1d..ebd86380b7 100644
--- a/packages/babel-cli/src/babel/dir.js
+++ b/packages/babel-cli/src/babel/dir.js
@@ -64,7 +64,7 @@ module.exports = function (commander, filenames) {
   _.each(filenames, handle);
 
   if (commander.watch) {
-    let chokidar = require("chokidar");
+    let chokidar = util.requireChokidar();
 
     _.each(filenames, function (dirname) {
       let watcher = chokidar.watch(dirname, {
diff --git a/packages/babel-cli/src/babel/file.js b/packages/babel-cli/src/babel/file.js
index 9ab05ed696..26fbaf3452 100644
--- a/packages/babel-cli/src/babel/file.js
+++ b/packages/babel-cli/src/babel/file.js
@@ -132,7 +132,7 @@ module.exports = function (commander, filenames, opts) {
     walk();
 
     if (commander.watch) {
-      let chokidar = require("chokidar");
+      let chokidar = util.requireChokidar();
       chokidar.watch(filenames, {
         persistent: true,
         ignoreInitial: true
diff --git a/packages/babel-cli/src/babel/util.js b/packages/babel-cli/src/babel/util.js
index 720705001a..e0d004fcb8 100644
--- a/packages/babel-cli/src/babel/util.js
+++ b/packages/babel-cli/src/babel/util.js
@@ -71,3 +71,12 @@ process.on("uncaughtException", function (err) {
   console.error(toErrorStack(err));
   process.exit(1);
 });
+
+export function requireChokidar() {
+  try {
+    return require("chokidar");
+  } catch (err) {
+    console.error("The optional dependency chokidar failed to install and is required for --watch. Chokidar is likely not supported on your platform.")
+    throw err;
+  }
+}