Add TypeScript types

Author: remcohaszing

README.md

@@ -49,12 +49,12 @@ module.exports = {
         plugins: [
           {
             resolve: `gatsby-remark-mermaid`,
-            options: {
+            options: /** @type {import('gatsby-remark-mermaid').Options} */ ({
               mermaidConfig: {
                 theme: 'neutral',
                 themeCSS: '.node rect { fill: #fff; }'
               }
-            }
+            })
           }
         ]
       }

index.d.ts

@@ -0,0 +1,12 @@
+import { RemarkMermaidOptions } from 'remark-mermaidjs'
+
+declare namespace gatsbyRemarkMermaid {
+  type Options = RemarkMermaidOptions
+}
+
+declare function gatsbyRemarkMermaid(
+  gatsbyRemarkOptions: unknown,
+  options: RemarkMermaidOptions
+): Promise<void>
+
+export = gatsbyRemarkMermaid

package.json

@@ -13,6 +13,7 @@
   "bugs": "https://github.com/remcohaszing/gatsby-remark-mermaid/issues",
   "homepage": "https://github.com/remcohaszing/gatsby-remark-mermaid#readme",
   "files": [
+    "index.d.ts",
     "index.js"
   ],
   "keywords": [