Fix build environment and link handling for both internal anchors and links to local documents

package.json

@@ -36,13 +36,6 @@
     "email": "ptheofan@gmail.com"
   },
   "license": "GPL-3.0",
-  "pnpm": {
-    "onlyBuiltDependencies": [
-      "electron",
-      "macos-alias",
-      "fs-xattr"
-    ]
-  },
   "devDependencies": {
     "@electron-forge/cli": "^7.11.1",
     "@electron-forge/maker-dmg": "^7.11.1",

pnpm-workspace.yaml

@@ -0,0 +1,8 @@
+allowBuilds:
+  electron: true
+  esbuild: true
+  fs-xattr: true
+  macos-alias: true
+nodeLinker: hoisted
+executionEnv:
+  nodeVersion: 22.17.0

src/plugins/builtin/GithubFlavoredPlugin.ts

@@ -56,6 +56,49 @@ export class GithubFlavoredPlugin implements MarkdownPlugin {
 
     // Add task list support
     this.addTaskLists(md);
+
+    // Add GitHub-style ids to headings so in-document anchors work
+    this.addHeadingAnchors(md);
+  }
+
+  /**
+   * Assign GitHub-style slug ids to headings (e.g. "TextField API" ->
+   * "textfield-api") so that in-document links like [foo](#textfield-api)
+   * resolve. Duplicate slugs get a numeric suffix, matching GitHub.
+   */
+  private addHeadingAnchors(md: MarkdownIt): void {
+    md.core.ruler.push('heading_anchors', (state) => {
+      const usedSlugs = new Map<string, number>();
+      const tokens = state.tokens;
+
+      for (let i = 0; i < tokens.length; i++) {
+        const token = tokens[i];
+        if (!token || token.type !== 'heading_open') continue;
+
+        const inline = tokens[i + 1];
+        if (!inline || inline.type !== 'inline') continue;
+
+        const text = (inline.children ?? [])
+          .filter((t) => t.type === 'text' || t.type === 'code_inline')
+          .map((t) => t.content)
+          .join('');
+
+        let slug = text
+          .trim()
+          .toLowerCase()
+          .replace(/[^\w\- ]+/g, '')
+          .replace(/\s+/g, '-');
+        if (!slug) continue;
+
+        const count = usedSlugs.get(slug) ?? 0;
+        usedSlugs.set(slug, count + 1);
+        if (count > 0) {
+          slug = `${slug}-${count}`;
+        }
+
+        token.attrSet('id', slug);
+      }
+    });
   }
 
   /**

src/preload/assetResolver.ts

@@ -11,14 +11,16 @@ import { pathToFileURL } from 'node:url';
 import { ASSET_PROTOCOL_SCHEME, ASSET_PROTOCOL_HOST } from '@shared/constants';
 
 /**
- * Resolve an image reference against the markdown file that contains it.
+ * Resolve a document reference to an absolute filesystem path.
  *
  * @param baseFilePath - Absolute path to the markdown file being rendered.
- * @param ref - The raw `src`/`srcset` reference from the document.
- * @returns An `om-asset:` URL for local files, or `null` when the reference
- *   should be left untouched (already a URL, protocol-relative, or empty).
+ * @param ref - The raw reference from the document (e.g. `./other.md`,
+ *   `images/logo.svg`, `/abs/path/file.md`).
+ * @returns The absolute path on disk, or `null` when the reference is not a
+ *   local file (already a URL, protocol-relative, in-document anchor, or
+ *   empty). Query strings and fragments are stripped.
  */
-export function resolveAssetUrl(baseFilePath: string, ref: string): string | null {
+export function resolveLocalPath(baseFilePath: string, ref: string): string | null {
   if (!baseFilePath || !ref) {
     return null;
   }
@@ -35,7 +37,7 @@ export function resolveAssetUrl(baseFilePath: string, ref: string): string | nul
     return null;
   }
 
-  // Pure in-document anchors are not assets.
+  // Pure in-document anchors are not local files.
   if (trimmed.startsWith('#')) {
     return null;
   }
@@ -53,9 +55,24 @@ export function resolveAssetUrl(baseFilePath: string, ref: string): string | nul
     decoded = cleaned;
   }
 
-  const resolved = path.isAbsolute(decoded)
+  return path.isAbsolute(decoded)
     ? decoded
     : path.resolve(path.dirname(baseFilePath), decoded);
+}
+
+/**
+ * Resolve an image reference against the markdown file that contains it.
+ *
+ * @param baseFilePath - Absolute path to the markdown file being rendered.
+ * @param ref - The raw `src`/`srcset` reference from the document.
+ * @returns An `om-asset:` URL for local files, or `null` when the reference
+ *   should be left untouched (already a URL, protocol-relative, or empty).
+ */
+export function resolveAssetUrl(baseFilePath: string, ref: string): string | null {
+  const resolved = resolveLocalPath(baseFilePath, ref);
+  if (!resolved) {
+    return null;
+  }
 
   // Embed the (already percent-encoded) file path under a fixed host. A bare
   // `om-asset:///path` URL is mangled by Chromium's standard-scheme parser,

src/preload/preload.ts

@@ -5,7 +5,7 @@
 import { contextBridge, ipcRenderer, webUtils } from 'electron';
 
 import { IPC_CHANNELS } from '@shared/types/api';
-import { resolveAssetUrl } from './assetResolver';
+import { resolveAssetUrl, resolveLocalPath } from './assetResolver';
 
 import type {
   ElectronAPI,
@@ -339,6 +339,10 @@ const electronAPI: ElectronAPI = {
     resolve: (baseFilePath: string, ref: string): string | null => {
       return resolveAssetUrl(baseFilePath, ref);
     },
+
+    resolvePath: (baseFilePath: string, ref: string): string | null => {
+      return resolveLocalPath(baseFilePath, ref);
+    },
   },
 
 };

src/renderer.ts

@@ -280,6 +280,14 @@ class App {
       },
     });
 
+    this.markdownViewer.setOnOpenLocalFile((filePath, fragment) => {
+      void this.loadFile(filePath).then(() => {
+        if (fragment) {
+          this.markdownViewer?.scrollToHeading(fragment);
+        }
+      });
+    });
+
     this.dropZone.setOnFileDrop((filePath) => {
       void this.handleFileDrop(filePath);
     });

src/renderer/components/MarkdownViewer.ts

@@ -9,7 +9,7 @@ import {
   createMermaidPlugin,
   MermaidPlugin,
 } from '@plugins/index';
-import { BUILTIN_PLUGINS } from '@shared/constants';
+import { BUILTIN_PLUGINS, MARKDOWN_EXTENSIONS } from '@shared/constants';
 import { Toast } from './Toast';
 
 import { EditModeController, createEditModeController } from './EditModeController';
@@ -49,6 +49,9 @@ export class MarkdownViewer {
   private toast: Toast;
   private editModeController: EditModeController | null = null;
   private isEditMode = false;
+  private onOpenLocalFile:
+    | ((filePath: string, fragment: string | null) => void)
+    | null = null;
 
   constructor(container: HTMLElement) {
     this.container = container;
@@ -338,13 +341,59 @@ export class MarkdownViewer {
       if (!(anchor instanceof HTMLAnchorElement)) return;
 
       const href = anchor.getAttribute('href');
-      if (!href || !this.isExternalUrl(href)) return;
+      if (!href) return;
 
+      // In-document anchor links: scroll to the target heading
+      if (href.startsWith('#')) {
+        e.preventDefault();
+        this.scrollToHeading(decodeURIComponent(href.slice(1)));
+        return;
+      }
+
+      if (this.isExternalUrl(href)) {
+        e.preventDefault();
+        void window.electronAPI.shell.openExternal(href);
+        return;
+      }
+
+      // Anything else is a local reference. Default navigation would replace
+      // the whole app page (blanking it back to the welcome screen), so it is
+      // always prevented; markdown files are opened in the viewer instead.
       e.preventDefault();
-      void window.electronAPI.shell.openExternal(href);
+      this.openLocalLink(href);
     });
   }
 
+  /**
+   * Open a link to a local markdown file in the viewer, resolving relative
+   * references against the current document's location
+   */
+  private openLocalLink(href: string): void {
+    const basePath = this.state.filePath;
+    if (!basePath || !this.onOpenLocalFile) return;
+
+    const resolved = window.electronAPI.assets.resolvePath(basePath, href);
+    if (!resolved) return;
+
+    const ext = resolved.slice(resolved.lastIndexOf('.')).toLowerCase();
+    if (!(MARKDOWN_EXTENSIONS as readonly string[]).includes(ext)) return;
+
+    const hashIndex = href.indexOf('#');
+    const fragment =
+      hashIndex >= 0 ? decodeURIComponent(href.slice(hashIndex + 1)) : null;
+
+    this.onOpenLocalFile(resolved, fragment);
+  }
+
+  /**
+   * Set the callback invoked when a link to a local markdown file is clicked
+   */
+  setOnOpenLocalFile(
+    callback: (filePath: string, fragment: string | null) => void
+  ): void {
+    this.onOpenLocalFile = callback;
+  }
+
   /**
    * Determine whether a link points to the internet (vs. an in-document anchor)
    */

src/shared/types/api.ts

@@ -268,6 +268,13 @@ export interface AssetsAPI {
    * otherwise should be left untouched.
    */
   resolve: (baseFilePath: string, ref: string) => string | null;
+
+  /**
+   * Resolve a document reference (e.g. a link to another markdown file) to an
+   * absolute filesystem path. Returns `null` when the reference is not a
+   * local file (already a URL or an in-document anchor).
+   */
+  resolvePath: (baseFilePath: string, ref: string) => string | null;
 }
 
 /**