chore: safe copy mechanism (#480)

Author: ovflowd

src/generators/legacy-html/index.mjs

@@ -1,12 +1,13 @@
 'use strict';
 
-import { cp, readFile, rm, writeFile } from 'node:fs/promises';
+import { readFile, rm, writeFile, mkdir } from 'node:fs/promises';
 import { join } from 'node:path';
 
 import HTMLMinifier from '@minify-html/node';
 
 import buildContent from './utils/buildContent.mjs';
 import dropdowns from './utils/buildDropdowns.mjs';
+import { safeCopy } from './utils/safeCopy.mjs';
 import tableOfContents from './utils/tableOfContents.mjs';
 import { groupNodesByModule } from '../../utils/generators.mjs';
 import { getRemarkRehype } from '../../utils/remark.mjs';
@@ -169,6 +170,9 @@ export default {
     }
 
     if (output) {
+      // Define the source folder for API docs assets
+      const srcAssets = join(baseDir, 'assets');
+
       // Define the output folder for API docs assets
       const assetsFolder = join(output, 'assets');
 
@@ -177,13 +181,11 @@ export default {
       // If the path does not exists, it will simply ignore and continue
       await rm(assetsFolder, { recursive: true, force: true, maxRetries: 10 });
 
-      // We copy all the other assets to the output folder at the end of the process
-      // to ensure that all latest changes on the styles are applied to the output
-      // Note.: This is not meant to be used for DX/developer purposes.
-      await cp(join(baseDir, 'assets'), assetsFolder, {
-        recursive: true,
-        force: true,
-      });
+      // Creates the assets folder if it does not exist
+      await mkdir(assetsFolder, { recursive: true });
+
+      // Copy all files from assets folder to output, skipping unchanged files
+      await safeCopy(srcAssets, assetsFolder);
     }
 
     return generatedValues;

src/generators/legacy-html/utils/safeCopy.mjs

@@ -0,0 +1,38 @@
+'use strict';
+
+import { readFile, writeFile, stat, readdir } from 'node:fs/promises';
+import { join } from 'node:path';
+
+/**
+ * Safely copies files from source to target directory, skipping files that haven't changed
+ * based on file stats (size and modification time)
+ *
+ * @param {string} srcDir - Source directory path
+ * @param {string} targetDir - Target directory path
+ */
+export async function safeCopy(srcDir, targetDir) {
+  const files = await readdir(srcDir);
+
+  for (const file of files) {
+    const sourcePath = join(srcDir, file);
+    const targetPath = join(targetDir, file);
+
+    const [sStat, tStat] = await Promise.allSettled([
+      stat(sourcePath),
+      stat(targetPath),
+    ]);
+
+    const shouldWrite =
+      tStat.status === 'rejected' ||
+      sStat.value.size !== tStat.value.size ||
+      sStat.value.mtimeMs > tStat.value.mtimeMs;
+
+    if (!shouldWrite) {
+      continue;
+    }
+
+    const fileContent = await readFile(sourcePath);
+
+    await writeFile(targetPath, fileContent);
+  }
+}