add option to emit obfuscated files

Author: David Sheldrick

src/__tests__/extendFileExtension.test.ts

@@ -0,0 +1,11 @@
+import { extendFileExtension } from "../extendFileExtension"
+
+describe("extendFileExtension", () => {
+  it("adds an extension part", () => {
+    expect(extendFileExtension("blah.js", "ext")).toBe("blah.ext.js")
+    expect(extendFileExtension("blah.tsx", "obfuscated")).toBe(
+      "blah.obfuscated.tsx",
+    )
+    expect(extendFileExtension("blah", "js")).toBe("blah.js")
+  })
+})

src/extendFileExtension.ts

@@ -0,0 +1,5 @@
+export function extendFileExtension(filename: string, extensionPart: string) {
+  const parts = filename.split(".")
+  parts.splice(1, 0, extensionPart)
+  return parts.join(".")
+}

src/obfuscatingTransformer.ts

@@ -17,6 +17,7 @@ import {
   obfuscateCode,
   obfuscateCodePreservingSourceMap,
 } from "./obfuscateCode"
+import { extendFileExtension } from "./extendFileExtension"
 
 function getOwnCacheKey(upstreamCacheKey: string, configFilename: string) {
   var key = crypto.createHash("md5")
@@ -31,6 +32,7 @@ export interface ObfuscatingTransformerOptions {
   upstreamTransformer?: MetroTransformer
   obfuscatorOptions?: JavaScriptObfuscator.Options
   trace?: boolean
+  emitObfuscatedFiles?: boolean
 }
 
 const sourceDir = path.join(appRootPath, "src")
@@ -79,6 +81,15 @@ export function obfuscatingTransformer({
           }
         }
 
+        if (otherOptions.emitObfuscatedFiles) {
+          const emitDir = path.dirname(props.filename)
+          const filename = extendFileExtension(
+            path.basename(props.filename),
+            "obfuscated",
+          )
+          fs.writeFileSync(path.join(emitDir, filename), code)
+        }
+
         return maybeTransformMetroResult(
           obfuscateCodePreservingSourceMap(
             code,