From 0678dad2d68ab4a0300e19a15493326fd105d3c3 Mon Sep 17 00:00:00 2001
From: Laurent Cozic <laurent@cozic.net>
Date: Wed, 4 Jan 2023 20:39:33 +0000
Subject: [PATCH] Tools: Speed up building mobile CodeMirror when nothing has
 changed

---
 .../CodeMirror/CodeMirror.bundle.js.md5        |  1 +
 packages/app-mobile/package.json               |  1 +
 packages/app-mobile/tools/buildInjectedJs.ts   | 18 +++++++++++++++++-
 yarn.lock                                      |  1 +
 4 files changed, 20 insertions(+), 1 deletion(-)
 create mode 100644 packages/app-mobile/components/NoteEditor/CodeMirror/CodeMirror.bundle.js.md5

diff --git a/packages/app-mobile/components/NoteEditor/CodeMirror/CodeMirror.bundle.js.md5 b/packages/app-mobile/components/NoteEditor/CodeMirror/CodeMirror.bundle.js.md5
new file mode 100644
index 0000000000..2c9eb93aa8
--- /dev/null
+++ b/packages/app-mobile/components/NoteEditor/CodeMirror/CodeMirror.bundle.js.md5
@@ -0,0 +1 @@
+0e1c132c199587530715a478bdb29a74
\ No newline at end of file
diff --git a/packages/app-mobile/package.json b/packages/app-mobile/package.json
index 709fe10561..b2fdaf8634 100644
--- a/packages/app-mobile/package.json
+++ b/packages/app-mobile/package.json
@@ -101,6 +101,7 @@
     "jest-environment-jsdom": "29.3.1",
     "jetifier": "2.0.0",
     "jsdom": "20.0.0",
+    "md5-file": "5.0.0",
     "metro-react-native-babel-preset": "0.67.0",
     "nodemon": "2.0.20",
     "ts-jest": "29.0.3",
diff --git a/packages/app-mobile/tools/buildInjectedJs.ts b/packages/app-mobile/tools/buildInjectedJs.ts
index 300303e45d..609a3033b4 100644
--- a/packages/app-mobile/tools/buildInjectedJs.ts
+++ b/packages/app-mobile/tools/buildInjectedJs.ts
@@ -3,8 +3,9 @@
 // files: First here we convert the JS file to a plain string, and that string
 // is then loaded by eg. the Mermaid plugin, and finally injected in the WebView.
 
-import { mkdirp, readFile, writeFile } from 'fs-extra';
+import { mkdirp, pathExists, readFile, writeFile } from 'fs-extra';
 import { dirname, extname, basename } from 'path';
+const md5File = require('md5-file');
 const execa = require('execa');
 
 // We need this to be transpiled to `const webpack = require('webpack')`.
@@ -77,19 +78,34 @@ class BundledFile {
 			resolve: {
 				extensions: ['.tsx', '.ts', '.js'],
 			},
+			cache: {
+				type: 'filesystem',
+			},
 		};
 
 		return config;
 	}
 
 	private async uglify() {
+		const md5Path = `${this.bundleOutputPath}.md5`;
+		const newMd5 = await md5File(this.bundleOutputPath);
+		const previousMd5 = await pathExists(md5Path) ? await readFile(md5Path, 'utf8') : '';
+
+		if (newMd5 === previousMd5 && await pathExists(this.bundleMinifiedPath)) {
+			console.info('Bundle has not changed - skipping minifying...');
+			return;
+		}
+
 		console.info(`Minifying bundle: ${this.bundleName}...`);
+
 		await execa('yarn', [
 			'run', 'uglifyjs',
 			'--compress',
 			'-o', this.bundleMinifiedPath,
 			this.bundleOutputPath,
 		]);
+
+		await writeFile(md5Path, newMd5, 'utf8');
 	}
 
 	private handleErrors(err: Error | undefined | null, stats: webpack.Stats | undefined): boolean {
diff --git a/yarn.lock b/yarn.lock
index c3e18a4c7d..bc3b3bb5e0 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -4713,6 +4713,7 @@ __metadata:
     jsc-android: 241213.1.0
     jsdom: 20.0.0
     md5: 2.3.0
+    md5-file: 5.0.0
     metro-react-native-babel-preset: 0.67.0
     nodemon: 2.0.20
     prop-types: 15.8.1