Convert server "object exists" functions to async/await.

server/controllers/collection.controller/collectionForUserExists.js

@@ -1,30 +1,17 @@
 import Collection from '../../models/collection';
 import User from '../../models/user';
 
-export default function collectionForUserExists(
-  username,
-  collectionId,
-  callback
-) {
-  function sendFailure() {
-    callback(false);
-  }
-
-  function sendSuccess(collection) {
-    callback(collection != null);
-  }
-
-  function findUser() {
-    return User.findByUsername(username);
-  }
-
-  function findCollection(owner) {
-    if (owner == null) {
-      throw new Error('User not found');
-    }
-
-    return Collection.findOne({ _id: collectionId, owner });
-  }
-
-  return findUser().then(findCollection).then(sendSuccess).catch(sendFailure);
+/**
+ * @param {string} username
+ * @param {string} collectionId
+ * @return {Promise<boolean>}
+ */
+export default async function collectionForUserExists(username, collectionId) {
+  const user = await User.findByUsername(username);
+  if (!user) return false;
+  const collection = await Collection.findOne({
+    _id: collectionId,
+    owner: user
+  }).exec();
+  return collection != null;
 }

server/controllers/project.controller.js

@@ -169,29 +169,28 @@ export function getProjects(req, res) {
   }
 }
 
-export function projectExists(projectId, callback) {
-  Project.findById(projectId, (err, project) =>
-    project ? callback(true) : callback(false)
-  );
+/**
+ * @param {string} projectId
+ * @return {Promise<boolean>}
+ */
+export async function projectExists(projectId) {
+  const project = await Project.findById(projectId);
+  return project != null;
 }
 
-export function projectForUserExists(username, projectId, callback) {
-  User.findByUsername(username, (err, user) => {
-    if (!user) {
-      callback(false);
-      return;
-    }
-    Project.findOne(
-      { user: user._id, $or: [{ _id: projectId }, { slug: projectId }] },
-      (innerErr, project) => {
-        if (!project) {
-          callback(false);
-          return;
-        }
-        callback(true);
-      }
-    );
+/**
+ * @param {string} username
+ * @param {string} projectId
+ * @return {Promise<boolean>}
+ */
+export async function projectForUserExists(username, projectId) {
+  const user = await User.findByUsername(username);
+  if (!user) return false;
+  const project = await Project.findOne({
+    user: user._id,
+    $or: [{ _id: projectId }, { slug: projectId }]
   });
+  return project != null;
 }
 
 function bundleExternalLibs(project) {

server/controllers/user.controller.js

@@ -308,10 +308,13 @@ export function updatePassword(req, res) {
   // eventually send email that the password has been reset
 }
 
-export function userExists(username, callback) {
-  User.findByUsername(username, (err, user) =>
-    user ? callback(true) : callback(false)
-  );
+/**
+ * @param {string} username
+ * @return {Promise<boolean>}
+ */
+export async function userExists(username) {
+  const user = await User.findByUsername(username);
+  return user != null;
 }
 
 export function saveUser(res, user) {

server/routes/server.routes.js

@@ -1,6 +1,5 @@
 import { Router } from 'express';
-import { renderIndex } from '../views/index';
-import { get404Sketch } from '../views/404Page';
+import sendHtml, { renderIndex } from '../views/index';
 import { userExists } from '../controllers/user.controller';
 import {
   projectExists,
@@ -27,40 +26,46 @@ router.get('/signup', (req, res) => {
   return res.send(renderIndex());
 });
 
-router.get('/projects/:project_id', (req, res) => {
-  projectExists(req.params.project_id, (exists) =>
-    exists ? res.send(renderIndex()) : get404Sketch((html) => res.send(html))
-  );
+router.get('/projects/:project_id', async (req, res) => {
+  const exists = await projectExists(req.params.project_id);
+  sendHtml(req, res, exists);
 });
 
-router.get('/:username/sketches/:project_id/add-to-collection', (req, res) => {
-  projectForUserExists(req.params.username, req.params.project_id, (exists) =>
-    exists ? res.send(renderIndex()) : get404Sketch((html) => res.send(html))
-  );
-});
+router.get(
+  '/:username/sketches/:project_id/add-to-collection',
+  async (req, res) => {
+    const exists = await projectForUserExists(
+      req.params.username,
+      req.params.project_id
+    );
+    sendHtml(req, res, exists);
+  }
+);
 
-router.get('/:username/sketches/:project_id', (req, res) => {
-  projectForUserExists(req.params.username, req.params.project_id, (exists) =>
-    exists ? res.send(renderIndex()) : get404Sketch((html) => res.send(html))
+router.get('/:username/sketches/:project_id', async (req, res) => {
+  const exists = await projectForUserExists(
+    req.params.username,
+    req.params.project_id
   );
+  sendHtml(req, res, exists);
 });
 
-router.get('/:username/sketches', (req, res) => {
-  userExists(req.params.username, (exists) =>
-    exists ? res.send(renderIndex()) : get404Sketch((html) => res.send(html))
-  );
+router.get('/:username/sketches', async (req, res) => {
+  const exists = await userExists(req.params.username);
+  sendHtml(req, res, exists);
 });
 
-router.get('/:username/full/:project_id', (req, res) => {
-  projectForUserExists(req.params.username, req.params.project_id, (exists) =>
-    exists ? res.send(renderIndex()) : get404Sketch((html) => res.send(html))
+router.get('/:username/full/:project_id', async (req, res) => {
+  const exists = await projectForUserExists(
+    req.params.username,
+    req.params.project_id
   );
+  sendHtml(req, res, exists);
 });
 
-router.get('/full/:project_id', (req, res) => {
-  projectExists(req.params.project_id, (exists) =>
-    exists ? res.send(renderIndex()) : get404Sketch((html) => res.send(html))
-  );
+router.get('/full/:project_id', async (req, res) => {
+  const exists = await projectExists(req.params.project_id);
+  sendHtml(req, res, exists);
 });
 
 router.get('/login', (req, res) => {
@@ -98,15 +103,11 @@ router.get('/assets', (req, res) => {
   }
 });
 
-router.get('/:username/assets', (req, res) => {
-  userExists(req.params.username, (exists) => {
-    const isLoggedInUser =
-      req.user && req.user.username === req.params.username;
-    const canAccess = exists && isLoggedInUser;
-    return canAccess
-      ? res.send(renderIndex())
-      : get404Sketch((html) => res.send(html));
-  });
+router.get('/:username/assets', async (req, res) => {
+  const exists = await userExists(req.params.username);
+  const isLoggedInUser = req.user && req.user.username === req.params.username;
+  const canAccess = exists && isLoggedInUser;
+  sendHtml(req, res, canAccess);
 });
 
 router.get('/account', (req, res) => {
@@ -121,16 +122,17 @@ router.get('/about', (req, res) => {
   res.send(renderIndex());
 });
 
-router.get('/:username/collections/:id', (req, res) => {
-  collectionForUserExists(req.params.username, req.params.id, (exists) =>
-    exists ? res.send(renderIndex()) : get404Sketch((html) => res.send(html))
+router.get('/:username/collections/:id', async (req, res) => {
+  const exists = await collectionForUserExists(
+    req.params.username,
+    req.params.id
   );
+  sendHtml(req, res, exists);
 });
 
-router.get('/:username/collections', (req, res) => {
-  userExists(req.params.username, (exists) =>
-    exists ? res.send(renderIndex()) : get404Sketch((html) => res.send(html))
-  );
+router.get('/:username/collections', async (req, res) => {
+  const exists = await userExists(req.params.username);
+  sendHtml(req, res, exists);
 });
 
 router.get('/privacy-policy', (req, res) => {

server/views/index.js

@@ -1,3 +1,5 @@
+import get404Sketch from './404Page';
+
 export function renderIndex() {
   const assetsManifest = process.env.webpackAssets && JSON.parse(process.env.webpackAssets);
   return `
@@ -45,3 +47,18 @@ export function renderIndex() {
   </html>
   `;
 }
+
+/**
+ * Send a 404 page if `exists` is false.
+ * @param {import('express').e.Request} req
+ * @param {import('express').e.Response} res
+ * @param {boolean} [exists]
+ */
+export default function sendHtml(req, res, exists = true) {
+  if (!exists) {
+    res.status(404);
+    get404Sketch((html) => res.send(html));
+  } else {
+    res.send(renderIndex());
+  }
+};