Typescriptify the main process code (4/N)

Summary: Skip the main process code bundling when nothing changed

Reviewed By: mweststrate

Differential Revision: D20030261

fbshipit-source-id: 78de87377afe7e768627059425c51081239687dd

package.json

@@ -108,6 +108,7 @@
     "jest-fetch-mock": "^3.0.0",
     "prettier": "^1.19.1",
     "react-async": "^10.0.0",
+    "recursive-readdir": "^2.2.2",
     "redux-mock-store": "^1.5.3",
     "ts-jest": "^25.1.0",
     "typescript": "^3.7.2"

scripts/build-utils.js

@@ -9,10 +9,22 @@
 
 const Metro = require('../static/node_modules/metro');
 const compilePlugins = require('../static/compilePlugins');
+const util = require('util');
 const tmp = require('tmp');
 const path = require('path');
 const fs = require('fs-extra');
 const cp = require('promisify-child-process');
+const recursiveReaddir = require('recursive-readdir');
+
+function mostRecentlyChanged(dir, ignores) {
+  return util
+    .promisify(recursiveReaddir)(dir, ignores)
+    .then(files =>
+      files
+        .map(f => fs.lstatSync(f).ctime)
+        .reduce((a, b) => (a > b ? a : b), new Date(0)),
+    );
+}
 
 function die(err) {
   console.error(err.stack);
@@ -81,9 +93,19 @@ function compile(buildFolder, entry) {
 }
 
 async function compileMain() {
+  const staticDir = path.resolve(__dirname, '..', 'static');
+  const out = path.join(staticDir, 'main.bundle.js');
+  // check if main needs to be compiled
+  if (await fs.pathExists(out)) {
+    const staticDirCtime = await mostRecentlyChanged(staticDir, ['*.bundle.*']);
+    const bundleCtime = (await fs.lstat(out)).ctime;
+    if (staticDirCtime < bundleCtime) {
+      console.log(`🥫  Using cached version of main bundle...`);
+      return;
+    }
+  }
   console.log(`⚙️  Compiling main bundle...`);
   try {
-    const staticDir = path.resolve(__dirname, '..', 'static');
     const config = Object.assign({}, await Metro.loadConfig(), {
       reporter: {update: () => {}},
       projectRoot: staticDir,
@@ -105,7 +127,7 @@ async function compileMain() {
     await Metro.runBuild(config, {
       platform: 'web',
       entry: path.join(staticDir, 'main.ts'),
-      out: path.join(staticDir, 'main.bundle.js'),
+      out,
       dev: false,
       minify: false,
       sourceMap: true,
@@ -116,7 +138,6 @@ async function compileMain() {
     die(err);
   }
 }
-
 function buildFolder() {
   // eslint-disable-next-line no-console
   console.log('Creating build directory');
@@ -130,7 +151,6 @@ function buildFolder() {
     });
   }).catch(die);
 }
-
 function getVersionNumber() {
   let {version} = require('../package.json');
   const buildNumber = process.argv.join(' ').match(/--version=(\d+)/);
@@ -139,7 +159,6 @@ function getVersionNumber() {
   }
   return version;
 }
-
 // Asynchronously determine current mercurial revision as string or `null` in case of any error.
 function genMercurialRevision() {
   return cp
@@ -147,7 +166,6 @@ function genMercurialRevision() {
     .catch(err => null)
     .then(res => (res && res.stdout) || null);
 }
-
 module.exports = {
   buildFolder,
   compile,

yarn.lock

@@ -6441,7 +6441,7 @@ mimic-response@^1.0.0, mimic-response@^1.0.1:
   resolved "https://registry.yarnpkg.com/mimic-response/-/mimic-response-1.0.1.tgz#4923538878eef42063cb8a3e3b0798781487ab1b"
   integrity sha512-j5EctnkH7amfV/q5Hgmoal1g2QHFJRraOtmx0JpIqkxhBhI/lJSl1nMpQ45hVarwNETOoWEimndZ4QK0RHxuxQ==
 
-minimatch@^3.0.2, minimatch@^3.0.4:
+minimatch@3.0.4, minimatch@^3.0.2, minimatch@^3.0.4:
   version "3.0.4"
   resolved "https://registry.yarnpkg.com/minimatch/-/minimatch-3.0.4.tgz#5166e286457f03306064be5497e8dbb0c3d32083"
   integrity sha512-yJHVQEhyqPLUTgt9B83PXu6W3rx4MvvHvSUvToogpwoGDOUQ+yDrR0HRot+yOCdCO7u4hX3pWft6kWBBcqh0UA==
@@ -7698,6 +7698,13 @@ recast@^0.16.1:
     private "~0.1.5"
     source-map "~0.6.1"
 
+recursive-readdir@^2.2.2:
+  version "2.2.2"
+  resolved "https://registry.yarnpkg.com/recursive-readdir/-/recursive-readdir-2.2.2.tgz#9946fb3274e1628de6e36b2f6714953b4845094f"
+  integrity sha512-nRCcW9Sj7NuZwa2XvH9co8NPeXUBhZP7CRKJtU+cS6PW9FpCIFoI5ib0NT1ZrbNuPoRy0ylyCaUL8Gih4LSyFg==
+  dependencies:
+    minimatch "3.0.4"
+
 redux-devtools-core@^0.2.1:
   version "0.2.1"
   resolved "https://registry.yarnpkg.com/redux-devtools-core/-/redux-devtools-core-0.2.1.tgz#4e43cbe590a1f18c13ee165d2d42e0bc77a164d8"