Chore/convert to typescript (#60)

* Convert to using TypeScript

Next.js v.9 allows converting an existing project to TS by simply renaming the files as TS files

* Fix type errors: Type 'string' is not assignable to type 'number'.

* Add mention about missing typings for javascript-time-ago

* Add GA_INITIALIZED to window

* Fix type error in feed transformers

* Model MembershipInfoForm state and props with TS

* Silence the typescript warning in MembershipInfoForm

* Add threshold to Fader props

* Fix Warning: Each child in a list should have a unique "key" prop.

Sponsors don't have ids – name is probably unique and can be used as a key

* Allow key as prop for SponsorLink

* Add type of the props for SponsorLink

components/feed-transformers.ts

@@ -0,0 +1,70 @@
+import lodashTemplate from "lodash/template";
+import defaultTemplateSettings from "lodash/templateSettings";
+import githubEvent from "parse-github-event";
+import twitterText from "twitter-text";
+
+const isVisibleGithubEvent = ({ type }) =>
+  type !== "PushEvent" && type !== "DeleteEvent";
+
+const templateSettings = {
+  ...defaultTemplateSettings,
+  interpolate: /{{([\s\S]+?)}}/g,
+};
+
+export default {
+  github(items) {
+    return items.filter(isVisibleGithubEvent).map(item => {
+      const template = lodashTemplate(
+        githubEvent.parse(item).text,
+        templateSettings,
+        false
+      );
+
+      const repository = `https://github.com/${item.repo.name}`;
+      let branch;
+      if (item.payload.ref) {
+        branch = item.payload.ref.replace("refs/heads/", "");
+      }
+
+      const message = template({
+        repository: `<a target="_blank" href="${repository}">${item.repo.name}</a>`,
+        branch: branch,
+        number: item.payload.number,
+        ref_type: item.payload.ref_type,
+        ref: item.payload.ref,
+      });
+
+      const url = `https://github.com/${item.actor.login}`;
+
+      return {
+        user: item.actor.login,
+        userLink: url,
+        image: item.actor.avatar_url,
+        imageLink: url,
+        body: message,
+        timestamp: new Date(item.created_at),
+        url: message.url,
+        type: "github",
+      };
+    });
+  },
+  twitter(items) {
+    return items.map(item => {
+      if (item.retweeted) {
+        item = item.retweeted_status;
+      }
+
+      const url = `https://twitter.com/${item.user.screen_name}`;
+
+      return {
+        user: `@${item.user.screen_name}`,
+        userLink: url,
+        image: item.user.profile_image_url_https,
+        imageLink: url,
+        body: twitterText.autoLink(item.text),
+        timestamp: new Date(item.created_at),
+        type: "twitter",
+      };
+    });
+  },
+};