Add markdownLinkExternal option

Resolves #2679

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ### Features
 
+-   Added `markdownLinkExternal` option to treat `http[s]://` links in markdown documents and comments as external to be opened in a new tab, #2679.
 -   Added `navigation.excludeReferences` option to prevent re-exports from appearing in the left hand navigation, #2685.
 
 ### Bug Fixes

src/lib/internationalization/translatable.ts

@@ -270,6 +270,8 @@ export const translatable = {
         "Set the CNAME file text, it's useful for custom domains on GitHub Pages",
     help_sourceLinkExternal:
         "Specifies that source links should be treated as external links to be opened in a new tab",
+    help_markdownLinkExternal:
+        "Specifies that http[s]:// links in comments and markdown files should be treated as external links to be opened in a new tab",
     help_githubPages:
         "Generate a .nojekyll file to prevent 404 errors in GitHub Pages. Defaults to `true`",
     help_hostedBaseUrl:

src/lib/output/themes/MarkedPlugin.tsx

@@ -36,6 +36,9 @@ export class MarkedPlugin extends ContextAwareRendererComponent {
     @Option("markdownItOptions")
     accessor markdownItOptions!: Record<string, unknown>;
 
+    @Option("markdownLinkExternal")
+    accessor markdownLinkExternal!: boolean;
+
     private parser?: markdown;
 
     /**
@@ -263,6 +266,14 @@ export class MarkedPlugin extends ContextAwareRendererComponent {
             const token = tokens[idx];
             const href = token.attrGet("href")?.replace(/^#(?:md:)?(.+)/, "#md:$1");
             if (href) {
+                // Note: This doesn't catch @link tags to reflections as those
+                // will be relative links. This will likely have to change with
+                // the introduction of support for customized routers whenever
+                // that becomes a real thing.
+                if (this.markdownLinkExternal && /https?:\/\//i.test(href)) {
+                    token.attrSet("target", "_blank");
+                }
+
                 token.attrSet("href", href);
             }
             return self.renderToken(tokens, idx, options);

src/lib/utils/options/declaration.ts

@@ -122,6 +122,7 @@ export interface TypeDocOptionMap {
     disableSources: boolean;
     sourceLinkTemplate: string;
     sourceLinkExternal: boolean;
+    markdownLinkExternal: boolean;
     disableGit: boolean;
     gitRevision: string;
     gitRemote: string;

src/lib/utils/options/sources/typedoc.ts

@@ -430,6 +430,12 @@ export function addTypeDocOptions(options: Pick<Options, "addDeclaration">) {
         help: (i18n) => i18n.help_sourceLinkExternal(),
         type: ParameterType.Boolean,
     });
+    options.addDeclaration({
+        name: "markdownLinkExternal",
+        help: (i18n) => i18n.help_markdownLinkExternal(),
+        type: ParameterType.Boolean,
+        defaultValue: true,
+    });
     options.addDeclaration({
         name: "githubPages",
         help: (i18n) => i18n.help_githubPages(),
@@ -440,7 +446,7 @@ export function addTypeDocOptions(options: Pick<Options, "addDeclaration">) {
         name: "hostedBaseUrl",
         help: (i18n) => i18n.help_hostedBaseUrl(),
         validate(value, i18n) {
-            if (!/https?:\/\//.test(value)) {
+            if (!/https?:\/\//i.test(value)) {
                 throw new Error(i18n.hostedBaseUrl_must_start_with_http());
             }
         },