add tests

__tests__/lib/string.test.ts

@@ -1,5 +1,7 @@
 import {RichText} from '@atproto/api'
+import tldts from 'tldts'
 
+import {emailTypoCheck} from 'lib/strings/email-typo'
 import {parseEmbedPlayerFromUrl} from 'lib/strings/embed-player'
 import {
   createStarterPackGooglePlayUri,
@@ -985,3 +987,83 @@ describe('createStarterPackGooglePlayUri', () => {
     expect(createStarterPackGooglePlayUri(undefined, 'rkey')).toEqual(null)
   })
 })
+
+describe('emailTypoChecker', () => {
+  const invalidCases = [
+    'gnail.com',
+    'gnail.co',
+    'gmaill.com',
+    'gmaill.co',
+    'gmai.com',
+    'gmai.co',
+    'gmal.com',
+    'gmal.co',
+    'gmail.co',
+    'iclod.com',
+    'iclod.co',
+    'outllok.com',
+    'outllok.co',
+    'outlook.co',
+    'yaoo.com',
+    'yaoo.co',
+    'yaho.com',
+    'yaho.co',
+    'yahooo.com',
+    'yahooo.co',
+    'yahoo.co',
+    'hithere.jul',
+    'agpowj.notshop',
+    'thisisnot.avalid.tld.nope',
+    // old tld for czechoslovakia
+    'czechoslovakia.cs',
+    // tlds that cbs was registering in 2024 but cancelled
+    'liveon.cbs',
+    'its.showtime',
+  ]
+  const validCases = [
+    'gmail.com',
+    'outlook.com',
+    'yahoo.com',
+    'icloud.com',
+    'firefox.com',
+    'firefox.co',
+    'hello.world.com',
+    'buy.me.a.coffee.shop',
+    'mayotte.yt',
+    'aland.ax',
+    'bouvet.bv',
+    'uk.gb',
+    'chad.td',
+    'somalia.so',
+    'plane.aero',
+    'cute.cat',
+    'together.coop',
+    'findme.jobs',
+    'nightatthe.museum',
+    'industrial.mil',
+    'czechrepublic.cz',
+    'lovakia.sk',
+    // new gtlds in 2024
+    'whatsinyour.locker',
+    'letsmakea.deal',
+    'skeet.now',
+    'everyone.みんな',
+    'bourgeois.lifestyle',
+    'california.living',
+    'skeet.ing',
+    'listeningto.music',
+    'createa.meme',
+  ]
+
+  for (const domain of invalidCases) {
+    it(`returns true when calling emailTypoCheck for abcde@${domain}`, () => {
+      expect(emailTypoCheck(`abcde@${domain}`, tldts)).toEqual(true)
+    })
+  }
+
+  for (const domain of validCases) {
+    it(`returns false when calling emailTypoCheck for abcde@${domain}`, () => {
+      expect(emailTypoCheck(`abcde@${domain}`, tldts)).toEqual(false)
+    })
+  }
+})

src/lib/strings/email-typo.ts

@@ -0,0 +1,9 @@
+import type tldts from 'tldts'
+
+const COMMON_ERROR_PATTERN =
+  /\b([a-zA-Z0-9._%+-]+)@(gnail\.(co|com)|gmaill\.(co|com)|gmai\.(co|com)|gmail\.co|gmal\.(co|com)|iclod\.(co|com)|icloud\.co|outllok\.(co|com)|outlok\.(co|com)|outlook\.co|yaoo\.(co|com)|yaho\.(co|com)|yahoo\.co|yahooo\.(co|com))\b/
+
+export function emailTypoCheck(email: string, dynamicTldts: typeof tldts) {
+  const isIcann = dynamicTldts.parse(email).isIcann
+  return !isIcann || COMMON_ERROR_PATTERN.test(email)
+}

src/screens/Signup/StepInfo/index.tsx

@@ -7,6 +7,7 @@ import type tldts from 'tldts'
 
 import {logEvent} from '#/lib/statsig/statsig'
 import {logger} from '#/logger'
+import {emailTypoCheck} from 'lib/strings/email-typo'
 import {ScreenTransition} from '#/screens/Login/ScreenTransition'
 import {is13, is18, useSignupContext} from '#/screens/Signup/state'
 import {Policies} from '#/screens/Signup/StepInfo/Policies'
@@ -31,9 +32,6 @@ function sanitizeDate(date: Date): Date {
   return date
 }
 
-const COMMON_ERROR_PATTERN =
-  /\b([a-zA-Z0-9._%+-]+)@(gnail\.com|gmaill\.com|gmai\.com|gmail\.co|gmal\.com|iclod\.com|icloud\.co|outllok\.com|outlok\.com|outlook\.co|yaoo\.com|yaho\.com|yahoo\.co|yahooo\.com)\b/
-
 export function StepInfo({
   onPressBack,
   isServerError,
@@ -50,6 +48,7 @@ export function StepInfo({
 
   const inviteCodeValueRef = useRef<string>(state.inviteCode)
   const emailValueRef = useRef<string>(state.email)
+  const prevEmailValueRef = useRef<string>(state.email)
   const passwordValueRef = useRef<string>(state.password)
 
   const [hasWarnedEmail, setHasWarnedEmail] = React.useState<boolean>(false)
@@ -67,11 +66,12 @@ export function StepInfo({
   const onNextPress = () => {
     const inviteCode = inviteCodeValueRef.current
     const email = emailValueRef.current
+    const emailChanged = prevEmailValueRef.current !== email
     const password = passwordValueRef.current
 
-    if (!hasWarnedEmail && tldtsRef.current) {
-      const isIcann = tldtsRef.current.parse(email).isIcann
-      if (!isIcann || COMMON_ERROR_PATTERN.test(email)) {
+    if (emailChanged && tldtsRef.current) {
+      if (emailTypoCheck(email, tldtsRef.current)) {
+        prevEmailValueRef.current = email
         setHasWarnedEmail(true)
         return dispatch({
           type: 'setError',
@@ -83,6 +83,7 @@ export function StepInfo({
     } else if (hasWarnedEmail) {
       setHasWarnedEmail(false)
     }
+    prevEmailValueRef.current = email
 
     if (!is13(state.dateOfBirth)) {
       return