refactor(v2): merge linkify function used in blog and docs and align properties (#4402)

* refactor(v2): merge linkify function used in blog and docs

* refactor(v2): rename docsDirPath and docsDirPathLocalized ad update types

* refactor(v2): rename blogPostsBySource and update types

* improve replaceMarkdownLinks api

Co-authored-by: slorber <lorber.sebastien@gmail.com>

packages/docusaurus-utils/src/markdownLinks.ts

@@ -0,0 +1,93 @@
+/**
+ * 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 {resolve} from 'url';
+import {aliasedSitePath} from './index';
+
+export type ContentPaths = {
+  contentPath: string;
+  contentPathLocalized: string;
+};
+
+export type BrokenMarkdownLink<T extends ContentPaths> = {
+  filePath: string;
+  contentPaths: T;
+  link: string;
+};
+
+export type ReplaceMarkdownLinksParams<T extends ContentPaths> = {
+  siteDir: string;
+  fileString: string;
+  filePath: string;
+  contentPaths: T;
+  sourceToPermalink: Record<string, string>;
+};
+
+export type ReplaceMarkdownLinksReturn<T extends ContentPaths> = {
+  newContent: string;
+  brokenMarkdownLinks: BrokenMarkdownLink<T>[];
+};
+
+export function replaceMarkdownLinks<T extends ContentPaths>({
+  siteDir,
+  fileString,
+  filePath,
+  contentPaths,
+  sourceToPermalink,
+}: ReplaceMarkdownLinksParams<T>): ReplaceMarkdownLinksReturn<T> {
+  const {contentPath, contentPathLocalized} = contentPaths;
+
+  const brokenMarkdownLinks: BrokenMarkdownLink<T>[] = [];
+
+  // Replace internal markdown linking (except in fenced blocks).
+  let fencedBlock = false;
+  const lines = fileString.split('\n').map((line) => {
+    if (line.trim().startsWith('```')) {
+      fencedBlock = !fencedBlock;
+    }
+    if (fencedBlock) {
+      return line;
+    }
+
+    let modifiedLine = line;
+    // Replace inline-style links or reference-style links e.g:
+    // This is [Document 1](doc1.md) -> we replace this doc1.md with correct link
+    // [doc1]: doc1.md -> we replace this doc1.md with correct link
+    const mdRegex = /(?:(?:\]\()|(?:\]:\s?))(?!https)([^'")\]\s>]+\.mdx?)/g;
+    let mdMatch = mdRegex.exec(modifiedLine);
+    while (mdMatch !== null) {
+      // Replace it to correct html link.
+      const mdLink = mdMatch[1];
+
+      const aliasedSource = (source: string) =>
+        aliasedSitePath(source, siteDir);
+
+      const permalink: string | undefined =
+        sourceToPermalink[aliasedSource(resolve(filePath, mdLink))] ||
+        sourceToPermalink[aliasedSource(`${contentPathLocalized}/${mdLink}`)] ||
+        sourceToPermalink[aliasedSource(`${contentPath}/${mdLink}`)];
+
+      if (permalink) {
+        modifiedLine = modifiedLine.replace(mdLink, permalink);
+      } else {
+        const brokenMarkdownLink: BrokenMarkdownLink<T> = {
+          contentPaths,
+          filePath,
+          link: mdLink,
+        };
+
+        brokenMarkdownLinks.push(brokenMarkdownLink);
+      }
+      mdMatch = mdRegex.exec(modifiedLine);
+    }
+    return modifiedLine;
+  });
+
+  const newContent = lines.join('\n');
+
+  return {newContent, brokenMarkdownLinks};
+}