implement WebExtensionPackager

package.json

@@ -26,6 +26,7 @@
   "devDependencies": {
     "cross-env": "^5.1.6",
     "mocha": "^5.2.0",
-    "parcel-bundler": "^1.9.0"
+    "parcel-bundler": "^1.9.0",
+    "zip-dir": "^1.0.2"
   }
 }

src/ManifestAsset.js

@@ -17,7 +17,7 @@ class ManifestAsset extends Asset {
             return new JSONAsset(...arguments)
         }
 
-        this.type = basename === 'manifest.json' ? 'json' : 'webmanifest'
+        this.type = '@@webext'
         this.isAstDirty = false
     }
 

src/WebExtensionPackager.js

@@ -0,0 +1,56 @@
+const { promisify } = require('util')
+const zipDir = promisify(require('zip-dir'))
+const path = require('path')
+const fs = require('parcel-bundler/src/utils/fs')
+const Packager = require('parcel-bundler/src/packagers/Packager')
+
+class WebExtensionPackager extends Packager {
+    async addAsset(asset) {
+        const artifactsDir = path.resolve(
+            asset.options.outDir,
+            '..',
+            'artifacts'
+        )
+        await fs.mkdirp(artifactsDir)
+
+        // Write the manifest.json
+        const bundlePath = path.parse(this.bundle.name)
+        const contents = await this.resolveAssetContents(asset)
+        const manifestJsonFilename = path.resolve(
+            bundlePath.dir,
+            bundlePath.name + '.json'
+        )
+        await fs.writeFile(manifestJsonFilename, contents, { encoding: 'utf8' })
+
+        // Package the extension (XPI/CRX)
+        const zipped = await zipDir(this.options.outDir)
+        const zippedFilename = path.resolve(
+            artifactsDir,
+            bundlePath.name + '.zip'
+        )
+        this.size = zipped.length
+        await fs.writeFile(zippedFilename, zipped)
+    }
+
+    async resolveAssetContents(asset) {
+        let contents = asset.generated[this.bundle.type]
+        if (!contents || (contents && contents.path)) {
+            contents = await fs.readFile(contents ? contents.path : asset.name)
+        }
+        // Create sub-directories if needed
+        if (this.bundle.name.includes(path.sep)) {
+            await fs.mkdirp(path.dirname(this.bundle.name))
+        }
+        return contents
+    }
+
+    setup() {}
+
+    end() {}
+
+    getSize() {
+        return this.size || 0
+    }
+}
+
+module.exports = WebExtensionPackager

src/index.js

@@ -1,5 +1,6 @@
 function WebExtensionPlugin(bundler) {
     bundler.addAssetType('json', require.resolve('./ManifestAsset'))
+    bundler.addPackager('@@webext', require.resolve('./WebExtensionPackager'))
 }
 
 module.exports = WebExtensionPlugin

test/.gitignore

@@ -1 +1,2 @@
 dist/
+artifacts/

test/web-extension.js

@@ -8,7 +8,7 @@ describe('WebExtension', () => {
         const bundle = await bundler.bundle()
 
         await assertBundleTree(bundle, {
-            type: 'json',
+            type: '@@webext',
             assets: ['manifest.json'],
             childBundles: [
                 { name: 'background_script.js' },

yarn.lock

@@ -104,6 +104,10 @@ async-limiter@~1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/async-limiter/-/async-limiter-1.0.0.tgz#78faed8c3d074ab81f22b4e985d79e8738f720f8"
 
+async@^1.5.2:
+  version "1.5.2"
+  resolved "https://registry.yarnpkg.com/async/-/async-1.5.2.tgz#ec6a61ae56480c0c3cb241c95618e20892f9672a"
+
 atob@^2.1.1:
   version "2.1.1"
   resolved "https://registry.yarnpkg.com/atob/-/atob-2.1.1.tgz#ae2d5a729477f289d60dd7f96a6314a22dd6c22a"
@@ -2033,6 +2037,12 @@ json5@^1.0.1:
   dependencies:
     minimist "^1.2.0"
 
+jszip@^2.4.0:
+  version "2.6.1"
+  resolved "https://registry.yarnpkg.com/jszip/-/jszip-2.6.1.tgz#b88f3a7b2e67a2a048152982c7a3756d9c4828f0"
+  dependencies:
+    pako "~1.0.2"
+
 kind-of@^3.0.2, kind-of@^3.0.3, kind-of@^3.2.0:
   version "3.2.2"
   resolved "https://registry.yarnpkg.com/kind-of/-/kind-of-3.2.2.tgz#31ea21a734bab9bbb0f32466d893aea51e4a3c64"
@@ -2475,7 +2485,7 @@ pako@^0.2.5:
   version "0.2.9"
   resolved "https://registry.yarnpkg.com/pako/-/pako-0.2.9.tgz#f3f7522f4ef782348da8161bad9ecfd51bf83a75"
 
-pako@~1.0.5:
+pako@~1.0.2, pako@~1.0.5:
   version "1.0.6"
   resolved "https://registry.yarnpkg.com/pako/-/pako-1.0.6.tgz#0101211baa70c4bca4a0f63f2206e97b7dfaf258"
 
@@ -3643,3 +3653,10 @@ yallist@^2.1.2:
 yallist@^3.0.0, yallist@^3.0.2:
   version "3.0.2"
   resolved "https://registry.yarnpkg.com/yallist/-/yallist-3.0.2.tgz#8452b4bb7e83c7c188d8041c1a837c773d6d8bb9"
+
+zip-dir@^1.0.2:
+  version "1.0.2"
+  resolved "https://registry.yarnpkg.com/zip-dir/-/zip-dir-1.0.2.tgz#253f907aead62a21acd8721d8b88032b2411c051"
+  dependencies:
+    async "^1.5.2"
+    jszip "^2.4.0"