reduce io blocking ssr

api/resolvers/price.js

@@ -1,15 +1,7 @@
 const cache = new Map()
 const expiresIn = 30000 // in milliseconds
 
-async function getPrice (fiat) {
-  fiat ??= 'USD'
-  if (cache.has(fiat)) {
-    const { price, createdAt } = cache.get(fiat)
-    const expired = createdAt + expiresIn < Date.now()
-    if (!expired) {
-      return price
-    }
-  }
+async function fetchPrice (fiat) {
   const url = `https://api.coinbase.com/v2/prices/BTC-${fiat}/spot`
   const price = await fetch(url)
     .then((res) => res.json())
@@ -22,6 +14,17 @@ async function getPrice (fiat) {
   return price
 }
 
+async function getPrice (fiat) {
+  fiat ??= 'USD'
+  if (cache.has(fiat)) {
+    const { price, createdAt } = cache.get(fiat)
+    const expired = createdAt + expiresIn < Date.now()
+    if (expired) fetchPrice(fiat).catch(console.error) // update cache
+    return price // serve stale price (this on the SSR critical path)
+  }
+  return await fetchPrice(fiat)
+}
+
 export default {
   Query: {
     price: async (parent, { fiatCurrency }, ctx) => {

api/resolvers/user.js

@@ -62,12 +62,15 @@ async function authMethods (user, args, { models, me }) {
 
 export default {
   Query: {
-    me: async (parent, args, { models, me }) => {
+    me: async (parent, { skipUpdate }, { models, me }) => {
       if (!me) {
         return null
       }
 
-      return await models.user.update({ where: { id: me.id }, data: { lastSeenAt: new Date() } })
+      if (!skipUpdate) {
+        models.user.update({ where: { id: me.id }, data: { lastSeenAt: new Date() } }).catch(console.error)
+      }
+      return await models.user.findUnique({ where: { id: me.id } })
     },
     settings: async (parent, args, { models, me }) => {
       if (!me) {

api/ssrApollo.js

@@ -44,7 +44,8 @@ export function getGetServerSideProps (query, variables = null, notFoundFunc, re
     const client = await getSSRApolloClient(req)
 
     const { data: { me } } = await client.query({
-      query: ME
+      query: ME,
+      variables: { skipUpdate: true }
     })
 
     const { data: { price } } = await client.query({

api/typeDefs/user.js

@@ -2,7 +2,7 @@ import { gql } from 'apollo-server-micro'
 
 export default gql`
   extend type Query {
-    me: User
+    me(skipUpdate: Boolean): User
     settings: User
     user(name: String!): User
     users: [User!]