Add JSDoc based types

.gitignore

@@ -1,5 +1,6 @@
-.DS_Store
-*.log
 coverage/
 node_modules/
+.DS_Store
+*.d.ts
+*.log
 yarn.lock

formatters.js

@@ -1,23 +1,31 @@
+/**
+ * @typedef {import('remark-contributors').FormatterObjects} FormatterObjects
+ */
+
+/**
+ * @type {FormatterObjects}
+ */
 export const defaultFormatters = {
   email: {exclude: true},
   commits: {exclude: true},
   social: {
     label: 'Social',
     format(value) {
+      const object = /** @type {{url: string, text: string}|undefined} */ (
+        value
+      )
+
       // Shouldn’t happen, but let’s keep it here just to be sure.
       /* c8 ignore next 3 */
-      if (!value) {
+      if (!object) {
         return ''
       }
 
       return {
         type: 'link',
-        url: value.url,
+        url: object.url,
         children: [
-          {
-            type: 'strong',
-            children: [{type: 'text', value: value.text}]
-          }
+          {type: 'strong', children: [{type: 'text', value: object.text}]}
         ]
       }
     }