fix(tools): stop multiple prettier runs on large commits (#44124)

.lintstagedrc.js

@@ -2,31 +2,52 @@ const { ESLint } = require('eslint');
 
 const cli = new ESLint();
 
+// This lets us abort if we've already run a stage for all files
+const completedStages = new Set();
+
 // if a lot of files are changed, it's faster to run prettier/eslint on the
 // whole project than to run them on each file separately
 module.exports = {
   '*.(js|ts|tsx)': async files => {
+    if (completedStages.has('js')) return [];
+
     const ignoredIds = await Promise.all(
       files.map(file => cli.isPathIgnored(file))
     );
     const lintableFiles = files.filter((_, i) => !ignoredIds[i]);
-    return files.length > 10
-      ? ['eslint --max-warnings=0 --cache --fix .', 'prettier --write .']
-      : [
-          'eslint --max-warnings=0 --cache --fix ' + lintableFiles.join(' '),
-          ...files.map(filename => `prettier --write '${filename}'`)
-        ];
+    if (files.length > 10) {
+      completedStages.add('js');
+      return ['eslint --max-warnings=0 --cache --fix .', 'prettier --write .'];
+    } else {
+      return [
+        'eslint --max-warnings=0 --cache --fix ' + lintableFiles.join(' '),
+        ...files.map(filename => `prettier --write '${filename}'`)
+      ];
+    }
+  },
+  '*.!(js|ts|tsx)': files => {
+    if (completedStages.has('not-js')) return [];
+
+    if (files.length > 10) {
+      completedStages.add('not-js');
+      return 'prettier --write .';
+    } else {
+      return files.map(
+        filename => `prettier --write --ignore-unknown '${filename}'`
+      );
+    }
   },
-  '*.!(js|ts|tsx)': files =>
-    files.length > 10
-      ? 'prettier --write .'
-      : files.map(
-          filename => `prettier --write --ignore-unknown '${filename}'`
-        ),
-  './curriculum/challenges/**/*.md': files =>
-    files.length > 10
-      ? 'npm run lint:challenges'
-      : files.map(
-          filename => `node ./tools/scripts/lint/index.js '${filename}'`
-        )
+
+  './curriculum/challenges/**/*.md': files => {
+    if (completedStages.has('markdown')) return [];
+
+    if (files.length > 10) {
+      completedStages.add('markdown');
+      return 'npm run lint:challenges';
+    } else {
+      return files.map(
+        filename => `node ./tools/scripts/lint/index.js '${filename}'`
+      );
+    }
+  }
 };