Add new files to the main bundle tree. And remove them when they're r…

…emoved (parcel-bundler#667)

packages/core/parcel-bundler/src/Bundler.js

@@ -19,7 +19,7 @@ const installPackage = require('./utils/installPackage');
 const bundleReport = require('./utils/bundleReport');
 const prettifyTime = require('./utils/prettifyTime');
 const getRootDir = require('./utils/getRootDir');
-const {glob} = require('./utils/glob');
+const {glob, isGlob} = require('./utils/glob');
 
 /**
  * The Bundler is the main entry point. It resolves and loads assets,
@@ -59,6 +59,7 @@ class Bundler extends EventEmitter {
     this.pending = false;
     this.loadedAssets = new Map();
     this.watchedAssets = new Map();
+    this.watchedGlobs = entryFiles.filter(entry => isGlob(entry));
 
     this.farm = null;
     this.watcher = null;
@@ -372,7 +373,12 @@ class Bundler extends EventEmitter {
       if (process.env.NODE_ENV === 'test' && !this.watcher.ready) {
         await new Promise(resolve => this.watcher.once('ready', resolve));
       }
+      this.watchedGlobs.forEach(glob => {
+        this.watcher.add(glob);
+      });
+      this.watcher.on('add', this.onAdd.bind(this));
       this.watcher.on('change', this.onChange.bind(this));
+      this.watcher.on('unlink', this.onUnlink.bind(this));
     }
 
     if (this.options.hmr) {
@@ -758,7 +764,24 @@ class Bundler extends EventEmitter {
     }
   }
 
+  async onAdd(path) {
+    path = Path.join(process.cwd(), path);
+
+    let asset = this.parser.getAsset(path, this.options);
+    this.loadedAssets.set(path, asset);
+
+    this.entryAssets.add(asset);
+
+    await this.watch(path, asset);
+    this.onChange(path);
+  }
+
   async onChange(path) {
+    // The path to the newly-added items are not absolute.
+    if (!Path.isAbsolute(path)) {
+      path = Path.resolve(process.cwd(), path);
+    }
+
     let assets = this.watchedAssets.get(path);
     if (!assets || !assets.size) {
       return;
@@ -779,6 +802,17 @@ class Bundler extends EventEmitter {
     }, 100);
   }
 
+  async onUnlink(path) {
+    // The path to the newly-added items are not absolute.
+    if (!Path.isAbsolute(path)) {
+      path = Path.resolve(process.cwd(), path);
+    }
+
+    let asset = this.getLoadedAsset(path);
+    this.entryAssets.delete(asset);
+    this.unloadAsset(asset);
+  }
+
   middleware() {
     this.bundle();
     return Server.middleware(this);