refactor: use TypeScript for some middleware

Refs #398

package.json

@@ -163,6 +163,7 @@
     "@parcel/transformer-typescript-tsc": "2.0.0-beta.2",
     "@parcel/validator-typescript": "2.0.0-beta.2",
     "@types/doi-regex": "^0.1.0",
+    "@types/email-templates": "^8.0.4",
     "@types/faker": "^5.5.9",
     "@types/identifiers-arxiv": "^0.1.0",
     "@types/jest": "^27.0.2",
@@ -177,6 +178,8 @@
     "@types/koa__cors": "^2.2.3",
     "@types/node": "^14.17.32",
     "@types/node-fetch": "^2.5.12",
+    "@types/nodemailer": "^6.4.4",
+    "@types/nodemailer-sendgrid": "^1.0.0",
     "@types/parcel-env": "^0.0.1",
     "@types/quill": "^1.3.10",
     "@types/react-dom": "^16.9.14",

src/backend/middleware/community.js → src/backend/middleware/community.ts

@@ -1,11 +1,14 @@
+import { Middleware } from 'koa';
+
 /**
  * Middleware shim to get current community and add it to context.
- *
- * @param {Object} ctx - the koa context object
- * @param {function} next - continue to next middleware
  */
 
-const currentCommunity = () => {
+type Community = {
+  community: string | null
+}
+
+const currentCommunity = (): Middleware<Community> => {
   return async (ctx, next) => {
     const path = ctx.request.path.replace(/^\/+|\/+$/g, '').split('/');
     if (path[0] === 'api' && path[2] === 'communities') {

src/backend/middleware/mail.js → src/backend/middleware/mail.ts

@@ -1,3 +1,4 @@
+import { DefaultState, Middleware } from 'koa';
 import path from 'path';
 import Email from 'email-templates';
 import nodemailer from 'nodemailer';
@@ -7,7 +8,16 @@ import sendgridTransport from 'nodemailer-sendgrid';
 
 const TEMPLATE_DIR = path.resolve('dist', 'backend', 'templates', 'email');
 
-export const mailWrapper = config => {
+type Config = {
+  emailAddress: string,
+  emailSendgridKey: string,
+}
+
+type Mailer = {
+  mail: Email;
+}
+
+export const mailWrapper = (config: Config): Middleware<DefaultState, Mailer> => {
   const transport = nodemailer.createTransport(
     sendgridTransport({
       apiKey: config.emailSendgridKey,

src/backend/middleware/persona.js → src/backend/middleware/persona.ts

@@ -1,11 +1,14 @@
+import { Middleware } from 'koa';
+
 /**
  * Middleware shim to get current persona and add it to context.
- *
- * @param {Object} ctx - the koa context object
- * @param {function} next - continue to next middleware
  */
 
-const currentPersona = () => {
+type Persona = {
+  persona: string | null;
+}
+
+const currentPersona = (): Middleware<Persona> => {
   return async (ctx, next) => {
     const path = ctx.request.path.replace(/^\/+|\/+$/g, '').split('/');
     if (path[0] === 'api' && path[2] === 'personas') {

src/backend/middleware/user.js → src/backend/middleware/user.ts

@@ -1,11 +1,14 @@
+import { Middleware } from 'koa';
+
 /**
  * Middleware shim to get current user and add it to context.
- *
- * @param {Object} ctx - the koa context object
- * @param {function} next - continue to next middleware
  */
 
-const currentUser = () => {
+type User = {
+  identity: string | null;
+}
+
+const currentUser = (): Middleware<User> => {
   return async (ctx, next) => {
     const path = ctx.request.path.replace(/^\/+|\/+$/g, '').split('/');
     if (path[0] === 'api' && path[2] === 'users') {

src/backend/server.ts

@@ -29,10 +29,10 @@ import { createError } from './utils/http-errors';
 
 // Our middlewares
 import authWrapper from './middleware/auth.js'; // authorization/user roles
-import currentCommunity from './middleware/community.js';
-import currentPersona from './middleware/persona.js';
-import currentUser from './middleware/user.js';
-import { mailWrapper } from './middleware/mail.js';
+import currentCommunity from './middleware/community';
+import currentPersona from './middleware/persona';
+import currentUser from './middleware/user';
+import { mailWrapper } from './middleware/mail';
 
 // Our models
 import {