feat: support reference-style linking in documents (#1048)

feat: support reference-style linking in documents

v1/lib/server/__tests__/__fixtures__/metadata.js

@@ -51,6 +51,21 @@ module.exports = {
     previous_title: 'Document 2',
     sort: 3,
   },
+  'en-reflinks': {
+    id: 'en-reflinks',
+    title: 'Reference Links',
+    source: 'reflinks.md',
+    version: 'next',
+    permalink: 'docs/en/next/reflinks.html',
+    localized_id: 'reflinks',
+    language: 'en',
+    sidebar: 'docs',
+    category: 'Test 2',
+    previous_id: 'doc3',
+    previous: 'en-doc3',
+    previous_title: 'Document 3',
+    sort: 4,
+  },
   'ko-doc1': {
     id: 'ko-doc1',
     title: '문서 1',

v1/lib/server/__tests__/__fixtures__/reflinks.md

@@ -0,0 +1,36 @@
+---
+id: reflinks
+title: Reference Links
+---
+
+### Existing Docs
+
+- [doc1][doc1]
+- [doc2][doc2]
+
+### Non-existing Docs
+
+- [hahaha][hahaha]
+
+## Repeating Docs
+
+- [doc1][doc1]
+- [doc2][doc2]
+
+## Do not replace this
+```md
+![image1][image1]
+```
+
+```js
+const doc1 = foo();
+console.log("[image2][image2]");
+const testStr = `![image3][image3]`;
+```
+
+[doc1]: doc1.md
+[doc2]: ./doc2.md
+[hahaha]: hahaha.md
+[image1]: assets/image1.png
+[image2]: assets/image2.jpg
+[image3]: assets/image3.gif

v1/lib/server/__tests__/__snapshots__/docs.test.js.snap

@@ -57,6 +57,42 @@ const testStr = \`![image3](assets/image3.gif)\`;
 \`\`\`"
 `;
 
+exports[`mdToHtmlify transforms reference links 1`] = `
+"
+### Existing Docs
+
+- [doc1][doc1]
+- [doc2][doc2]
+
+### Non-existing Docs
+
+- [hahaha][hahaha]
+
+## Repeating Docs
+
+- [doc1][doc1]
+- [doc2][doc2]
+
+## Do not replace this
+\`\`\`md
+![image1][image1]
+\`\`\`
+
+\`\`\`js
+const doc1 = foo();
+console.log(\\"[image2][image2]\\");
+const testStr = \`![image3][image3]\`;
+\`\`\`
+
+[doc1]: /docs/en/next/doc1
+[doc2]: /docs/en/next/doc2
+[hahaha]: hahaha.md
+[image1]: assets/image1.png
+[image2]: assets/image2.jpg
+[image3]: assets/image3.gif
+"
+`;
+
 exports[`replaceAssetsLink does not transform document without valid assets link 1`] = `
 "
 ### Existing Docs

v1/lib/server/__tests__/__snapshots__/readCategories.test.js.snap

@@ -64,6 +64,24 @@ Array [
         },
         "type": "LINK",
       },
+      Object {
+        "item": Object {
+          "category": "Test 2",
+          "id": "en-reflinks",
+          "language": "en",
+          "localized_id": "reflinks",
+          "permalink": "docs/en/next/reflinks.html",
+          "previous": "en-doc3",
+          "previous_id": "doc3",
+          "previous_title": "Document 3",
+          "sidebar": "docs",
+          "sort": 4,
+          "source": "reflinks.md",
+          "title": "Reference Links",
+          "version": "next",
+        },
+        "type": "LINK",
+      },
     ],
     "title": "Test 2",
     "type": "CATEGORY",

v1/lib/server/__tests__/docs.test.js

@@ -55,9 +55,15 @@ const doc3 = fs.readFileSync(
   'utf8',
 );
 
+const refLinks = fs.readFileSync(
+  path.join(__dirname, '__fixtures__', 'reflinks.md'),
+  'utf8',
+);
+
 const rawContent1 = metadataUtils.extractMetadata(doc1).rawContent;
 const rawContent2 = metadataUtils.extractMetadata(doc2).rawContent;
 const rawContent3 = metadataUtils.extractMetadata(doc3).rawContent;
+const rawContentRefLinks = metadataUtils.extractMetadata(refLinks).rawContent;
 
 describe('mdToHtmlify', () => {
   const mdToHtml = metadataUtils.mdToHtml(Metadata, '/');
@@ -105,6 +111,17 @@ describe('mdToHtmlify', () => {
     expect(content3).toMatchSnapshot();
     expect(content3).not.toEqual(rawContent3);
   });
+
+  test('transforms reference links', () => {
+    const contentRefLinks = docs.mdToHtmlify(
+      rawContentRefLinks,
+      mdToHtml,
+      Metadata['en-reflinks'],
+    );
+    expect(contentRefLinks).toContain('/docs/en/next/');
+    expect(contentRefLinks).toMatchSnapshot();
+    expect(contentRefLinks).not.toEqual(rawContentRefLinks);
+  });
 });
 
 describe('getFile', () => {

v1/lib/server/docs.js

@@ -48,16 +48,24 @@ function getFile(metadata) {
 function mdToHtmlify(oldContent, mdToHtml, metadata) {
   let content = oldContent;
   const mdLinks = [];
+  const mdReferences = [];
 
-  // find any links to markdown files
-  const regex = /(?:\]\()(?:\.\/)?([^'")\]\s>]+\.md)/g;
-  let match = regex.exec(content);
-  while (match !== null) {
-    mdLinks.push(match[1]);
-    match = regex.exec(content);
+  // find any inline-style links to markdown files
+  const linkRegex = /(?:\]\()(?:\.\/)?([^'")\]\s>]+\.md)/g;
+  let linkMatch = linkRegex.exec(content);
+  while (linkMatch !== null) {
+    mdLinks.push(linkMatch[1]);
+    linkMatch = linkRegex.exec(content);
+  }
+  // find any reference-style links to markdown files
+  const refRegex = /(?:\]:)(?:\s)?(?:\.\/|\.\.\/)?([^'")\]\s>]+\.md)/g;
+  let refMatch = refRegex.exec(content);
+  while (refMatch !== null) {
+    mdReferences.push(refMatch[1]);
+    refMatch = refRegex.exec(content);
   }
 
-  // replace to their website html links
+  // replace markdown links to their website html links
   new Set(mdLinks).forEach(mdLink => {
     let htmlLink = mdToHtml[mdLink];
     if (htmlLink) {
@@ -75,6 +83,25 @@ function mdToHtmlify(oldContent, mdToHtml, metadata) {
       );
     }
   });
+
+  // replace markdown refernces to their website html links
+  new Set(mdReferences).forEach(refLink => {
+    let htmlLink = mdToHtml[refLink];
+    if (htmlLink) {
+      htmlLink = getPath(htmlLink, siteConfig.cleanUrl);
+      htmlLink = htmlLink.replace('/en/', `/${metadata.language}/`);
+      htmlLink = htmlLink.replace(
+        '/VERSION/',
+        metadata.version && metadata.version !== env.versioning.latestVersion
+          ? `/${metadata.version}/`
+          : '/',
+      );
+      content = content.replace(
+        new RegExp(`\\]:(?:\\s)?(\\./|\\.\\./)?${refLink}`, 'g'),
+        `]: ${htmlLink}`,
+      );
+    }
+  });
   return content;
 }
 

v2/lib/webpack/loader/markdown.js

@@ -52,14 +52,31 @@ module.exports = function(fileString) {
       if (fencedBlock) return line;
 
       let modifiedLine = line;
-      const mdLinks = [];
-      const mdRegex = /(?:\]\()(?:\.\/)?([^'")\]\s>]+\.md)/g;
-      let match = mdRegex.exec(content);
-      while (match !== null) {
-        mdLinks.push(match[1]);
-        match = mdRegex.exec(content);
+      const inlineLinks = [];
+      const refLinks = [];
+
+      /* Replace inline-style links e.g: 
+      This is [Document 1](doc1.md) -> we replace this doc1.md with correct link
+      */
+      const inlineRegex = /(?:\]\()(?:\.\/)?([^'")\]\s>]+\.md)/g;
+      let inlineMatch = inlineRegex.exec(content);
+      while (inlineMatch !== null) {
+        inlineLinks.push(inlineMatch[1]);
+        inlineMatch = inlineRegex.exec(content);
+      }
+
+      /* Replace reference-style links e.g:  
+        This is [Document 1][doc1].
+        [doc1]: doc1.md -> we replace this doc1.md with correct link
+      */
+      const refRegex = /(?:\]:)(?:\s)?(?:\.\/|\.\.\/)?([^'")\]\s>]+\.md)/g;
+      let refMatch = refRegex.exec(content);
+      while (refMatch !== null) {
+        refLinks.push(refMatch[1]);
+        refMatch = refRegex.exec(content);
       }
-      mdLinks.forEach(mdLink => {
+
+      [...refLinks, ...inlineLinks].forEach(mdLink => {
         const targetSource = `${sourceDir}/${mdLink}`;
         const {permalink} = sourceToMetadata[targetSource] || {};
         if (permalink) {