refactor(utils): categorize functions into separate files (#6773)

packages/docusaurus-utils/src/emitUtils.ts

@@ -0,0 +1,113 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+import path from 'path';
+import fs from 'fs-extra';
+import {createHash} from 'crypto';
+import {simpleHash, docuHash} from './hashUtils';
+import {findAsyncSequential} from './jsUtils';
+
+const fileHash = new Map<string, string>();
+
+export async function generate(
+  generatedFilesDir: string,
+  file: string,
+  content: string,
+  skipCache: boolean = process.env.NODE_ENV === 'production',
+): Promise<void> {
+  const filepath = path.join(generatedFilesDir, file);
+
+  if (skipCache) {
+    await fs.ensureDir(path.dirname(filepath));
+    await fs.writeFile(filepath, content);
+    return;
+  }
+
+  let lastHash = fileHash.get(filepath);
+
+  // If file already exists but its not in runtime cache yet,
+  // we try to calculate the content hash and then compare
+  // This is to avoid unnecessary overwriting and we can reuse old file.
+  if (!lastHash && (await fs.pathExists(filepath))) {
+    const lastContent = await fs.readFile(filepath, 'utf8');
+    lastHash = createHash('md5').update(lastContent).digest('hex');
+    fileHash.set(filepath, lastHash);
+  }
+
+  const currentHash = createHash('md5').update(content).digest('hex');
+
+  if (lastHash !== currentHash) {
+    await fs.ensureDir(path.dirname(filepath));
+    await fs.writeFile(filepath, content);
+    fileHash.set(filepath, currentHash);
+  }
+}
+
+const chunkNameCache = new Map();
+
+/**
+ * Generate unique chunk name given a module path.
+ */
+export function genChunkName(
+  modulePath: string,
+  prefix?: string,
+  preferredName?: string,
+  shortId: boolean = process.env.NODE_ENV === 'production',
+): string {
+  let chunkName: string | undefined = chunkNameCache.get(modulePath);
+  if (!chunkName) {
+    if (shortId) {
+      chunkName = simpleHash(modulePath, 8);
+    } else {
+      let str = modulePath;
+      if (preferredName) {
+        const shortHash = simpleHash(modulePath, 3);
+        str = `${preferredName}${shortHash}`;
+      }
+      const name = str === '/' ? 'index' : docuHash(str);
+      chunkName = prefix ? `${prefix}---${name}` : name;
+    }
+    chunkNameCache.set(modulePath, chunkName);
+  }
+  return chunkName;
+}
+
+/**
+ * @param permalink The URL that the HTML file corresponds to, without base URL
+ * @param outDir Full path to the output directory
+ * @param trailingSlash The site config option. If provided, only one path will
+ * be read.
+ * @returns This returns a buffer, which you have to decode string yourself if
+ * needed. (Not always necessary since the output isn't for human consumption
+ * anyways, and most HTML manipulation libs accept buffers)
+ */
+export async function readOutputHTMLFile(
+  permalink: string,
+  outDir: string,
+  trailingSlash: boolean | undefined,
+): Promise<Buffer> {
+  const withTrailingSlashPath = path.join(outDir, permalink, 'index.html');
+  const withoutTrailingSlashPath = path.join(
+    outDir,
+    `${permalink.replace(/\/$/, '')}.html`,
+  );
+  if (trailingSlash) {
+    return fs.readFile(withTrailingSlashPath);
+  } else if (trailingSlash === false) {
+    return fs.readFile(withoutTrailingSlashPath);
+  }
+  const HTMLPath = await findAsyncSequential(
+    [withTrailingSlashPath, withoutTrailingSlashPath],
+    fs.pathExists,
+  );
+  if (!HTMLPath) {
+    throw new Error(
+      `Expected output HTML file to be found at ${withTrailingSlashPath}`,
+    );
+  }
+  return fs.readFile(HTMLPath);
+}