Require explicit function return types w/ ESLint.

.eslintrc.js

@@ -33,7 +33,6 @@ module.exports = {
     '@typescript-eslint/restrict-plus-operands': 'off',
     '@typescript-eslint/no-dynamic-delete': 'off',
     '@typescript-eslint/no-var-requires': 'off',
-    '@typescript-eslint/explicit-function-return-type': 'off', // TODO: Enable later.
     // Adjust to Prettier's presence. (Maybe we should do away with it later.)
     '@typescript-eslint/space-before-function-paren': 'off',
     '@typescript-eslint/member-delimiter-style': 'off',

src/App.tsx

@@ -43,9 +43,9 @@ export interface RootStackParamList {
   Home: undefined
   Chat: { serverName: string; version: number }
 }
-type HomeNavigationProp = NativeStackNavigationProp<RootStackParamList, 'Home'>
+type HomeProp = NativeStackNavigationProp<RootStackParamList, 'Home'>
 
-const HomeScreen = ({ navigation }: { navigation: HomeNavigationProp }) => {
+const HomeScreen = ({ navigation }: { navigation: HomeProp }): JSX.Element => {
   const { connection } = React.useContext(ConnectionContext)
   React.useEffect(() => {
     if (connection) {
@@ -92,7 +92,7 @@ const HomeScreen = ({ navigation }: { navigation: HomeNavigationProp }) => {
   )
 }
 
-const App = () => {
+const App = (): JSX.Element => {
   const [connection, setConnection] = React.useState<
     ServerConnection | undefined
   >()
@@ -109,9 +109,9 @@ const App = () => {
   const [serversStore, setServersStore] = useAsyncStorage('@servers', '{}')
   const accounts: Accounts = JSON.parse(accountsStore)
   const servers: Servers = JSON.parse(serversStore)
-  const setAccounts = (newAccounts: Accounts) =>
+  const setAccounts = (newAccounts: Accounts): void =>
     setAccountsStore(JSON.stringify(newAccounts))
-  const setServers = (newServers: Servers) =>
+  const setServers = (newServers: Servers): void =>
     setServersStore(JSON.stringify(newServers))
 
   const colorScheme = useColorScheme()

src/components/Dialog.tsx

@@ -17,7 +17,7 @@ const Dialog = ({
   visible: boolean
   onRequestClose: () => void
   containerStyles?: ViewStyle
-}>) => (
+}>): JSX.Element => (
   <Modal
     animationType='fade'
     transparent

src/components/DisconnectDialog.tsx

@@ -11,7 +11,7 @@ import {
 import Dialog, { dialogStyles } from './Dialog'
 import Text from './Text'
 
-const DisconnectDialog = () => {
+const DisconnectDialog = (): JSX.Element => {
   const darkMode = useDarkMode()
   const { disconnectReason, setDisconnectReason } =
     useContext(ConnectionContext)

src/components/ElevatedView.tsx

@@ -4,7 +4,7 @@ import useDarkMode from '../context/useDarkMode'
 
 const ElevatedView = (
   props: React.PropsWithChildren<{ style?: ViewStyle }>
-) => (
+): JSX.Element => (
   <View
     {...props}
     style={Object.assign(

src/components/Text.tsx

@@ -7,7 +7,7 @@ import {
 } from 'react-native'
 import useDarkMode from '../context/useDarkMode'
 
-const Text = (props: React.PropsWithChildren<TextProps>) => (
+const Text = (props: React.PropsWithChildren<TextProps>): JSX.Element => (
   <RNText
     {...props}
     style={[

src/components/TextField.tsx

@@ -2,7 +2,7 @@ import React from 'react'
 import { TextInput, StyleSheet, type TextInputProps } from 'react-native'
 import useDarkMode from '../context/useDarkMode'
 
-const TextField = (props: TextInputProps & { red?: boolean }) => {
+const TextField = (props: TextInputProps & { red?: boolean }): JSX.Element => {
   const style = props.style?.valueOf()
   const darkMode = useDarkMode()
   return (

src/components/TextFieldDialog.tsx

@@ -24,13 +24,13 @@ const TextFieldDialog = ({
   closeModal: () => void
   initialState: string
   setFinalState: (state: string) => void
-}) => {
+}): JSX.Element => {
   const [modalContent, setModalContent] = useState(initialState)
-  const closeModalAndSaveState = () => {
+  const closeModalAndSaveState = (): void => {
     setFinalState(modalContent)
     closeModal()
   }
-  const closeModalAndReset = () => {
+  const closeModalAndReset = (): void => {
     setModalContent(initialState)
     closeModal()
   }

src/components/accounts/AccountDisplay.tsx

@@ -16,7 +16,7 @@ const AccountDisplay = ({
   darkMode: boolean
   setActiveAccount: (uuid: string) => void
   setDeleteAccount: (uuid: string) => void
-}) => (
+}): JSX.Element => (
   <ElevatedView style={styles.accountView}>
     <Pressable
       onPress={() => setActiveAccount(uuid)}

src/components/accounts/AddAccountDialog.tsx

@@ -16,7 +16,7 @@ const AddAccountDialog = ({
 }: {
   open: boolean
   setOpen: React.Dispatch<React.SetStateAction<boolean>>
-}) => {
+}): JSX.Element => {
   const darkMode = useDarkMode()
   const { accounts, setAccounts } = useContext(UsersContext)
 
@@ -32,7 +32,7 @@ const AddAccountDialog = ({
     !/^[A-Za-z0-9_]{3,16}$/.test(newUser) &&
     (password === null ? true : !/^[^\s@]+@[^\s@]+$/.test(newUser))
 
-  const cancelAddAccount = () => {
+  const cancelAddAccount = (): void => {
     setMicrosoftLogin(false)
     setOpen(false)
     setUserRed(false)
@@ -41,7 +41,7 @@ const AddAccountDialog = ({
     setPassword(null) // setPassword('')
     setDialogError('')
   }
-  const addAccount = () => {
+  const addAccount = (): void => {
     const accountExists =
       !!accounts[newUser] ||
       !!Object.keys(accounts).find(id => accounts[id].email === newUser)

src/components/accounts/MicrosoftLogin.tsx

@@ -17,7 +17,7 @@ import {
 } from '../../minecraft/api/microsoft'
 import config from '../../../config.json'
 
-const MicrosoftLogin = ({ close }: { close: () => void }) => {
+const MicrosoftLogin = ({ close }: { close: () => void }): JSX.Element => {
   const darkMode = useDarkMode()
   const style = darkMode
     ? '<style>body{font-size:48px;padding:16px;background-color:#242424;color:#ffffff;}</style>'
@@ -27,7 +27,7 @@ const MicrosoftLogin = ({ close }: { close: () => void }) => {
   const webview = useRef<WebView>(null)
   const [loading, setLoading] = useState(false)
   const [html, setRawHtml] = useState('')
-  const setHtml = (newHtml: string) => setRawHtml(style + newHtml)
+  const setHtml = (newHtml: string): void => setRawHtml(style + newHtml)
 
   const addAccount = (
     id: string,
@@ -54,12 +54,12 @@ const MicrosoftLogin = ({ close }: { close: () => void }) => {
     return alreadyExists
   }
 
-  const onRequestClose = () => {
+  const onRequestClose = (): void => {
     if (!loading) close()
   }
   const handleNavigationStateChange = async (
     newNavState: WebViewNavigation
-  ) => {
+  ): Promise<void> => {
     // LOW-TODO: Parse errors.
     if (!webview.current || !newNavState.url) return
     if (

src/components/servers/EditServerDialog.tsx

@@ -27,7 +27,7 @@ const EditServerDialog = ({
   deleteServer: (server: string) => void
   editServerDialogOpen: string | boolean
   setEditServerDialogOpen: (server: string | boolean) => void
-}) => {
+}): JSX.Element => {
   const [ipAddr, setIpAddr] = useState('')
   const [ipAddrRed, setIpAddrRed] = useState(false)
   const [newServerName, setNewServerName] = useState('')
@@ -54,15 +54,15 @@ const EditServerDialog = ({
     }
   }, [editServerDialogOpen, server])
 
-  const closeDialog = () => setEditServerDialogOpen(false)
+  const closeDialog = (): void => setEditServerDialogOpen(false)
 
-  const handleDeleteServer = () => {
+  const handleDeleteServer = (): void => {
     if (typeof editServerDialogOpen !== 'string') return
     deleteServer(editServerDialogOpen)
     closeDialog()
   }
 
-  const handleEditServer = () => {
+  const handleEditServer = (): void => {
     const edit = typeof editServerDialogOpen === 'string'
     if (
       !newServerName ||

src/components/servers/ServerDisplay.tsx

@@ -29,7 +29,7 @@ const ServerDisplay = ({
   darkMode: boolean
   connectToServer: (server: string) => void
   openEditServerDialog: (server: string) => void
-}) => (
+}): JSX.Element => (
   <ElevatedView style={styles.serverView}>
     <Pressable
       onPress={() => connectToServer(server)}

src/components/settings/DarkModeSetting.tsx

@@ -15,7 +15,7 @@ import useDarkMode from '../../context/useDarkMode'
 const RadioButton = (props: {
   style?: StyleProp<ViewStyle>
   selected: boolean
-}) => {
+}): JSX.Element => {
   const darkMode = useDarkMode()
   return (
     <View
@@ -58,7 +58,10 @@ interface DarkModeSettingProps {
   setValue: (newValue: boolean | null) => void
 }
 
-const DarkModeSetting = ({ value, setValue }: DarkModeSettingProps) => {
+const DarkModeSetting = ({
+  value,
+  setValue
+}: DarkModeSettingProps): JSX.Element => {
   const [modalOpen, setModalOpen] = useState(false)
   const ripple = { color: '#aaa' }
   const dark = useDarkMode()

src/components/settings/Setting.tsx

@@ -20,7 +20,7 @@ const Setting = <T extends string | boolean>({
   setValue?: (newValue: T) => void
   multiline?: boolean
   maxLength?: number
-}) => {
+}): JSX.Element => {
   const da = useDarkMode()
   const [modalOpen, setModalOpen] = useState(false)
   const [modalContent, setModalContent] = useState(
@@ -30,7 +30,7 @@ const Setting = <T extends string | boolean>({
   const [toggleValue, setToggleValue] = useState(value)
 
   const Wrapper = setValue ?? onClick ? Pressable : React.Fragment
-  const wrapperPress = () => {
+  const wrapperPress = (): void => {
     if (onClick) onClick()
     else if (typeof value === 'boolean' && setValue) {
       setValue(!toggleValue as T)

src/context/useDarkMode.ts

@@ -2,6 +2,6 @@ import { createContext, useContext } from 'react'
 
 export const ColorSchemeContext = createContext<boolean>(false)
 
-const useDarkMode = () => useContext(ColorSchemeContext)
+const useDarkMode = (): boolean => useContext(ColorSchemeContext)
 
 export default useDarkMode

src/minecraft/api/microsoft.ts

@@ -115,7 +115,9 @@ export const authenticateWithXsts = async (
   return res.access_token
 }
 
-export const checkGameOwnership = async (accessToken: string) => {
+export const checkGameOwnership = async (
+  accessToken: string
+): Promise<boolean> => {
   const req = await fetch(mcStoreUrl, {
     headers: {
       Accept: 'application/json',
@@ -125,7 +127,7 @@ export const checkGameOwnership = async (accessToken: string) => {
   if (!req.ok) throw new Error('Failed to check if user owns Minecraft game!')
   const res = await req.json()
   const items = res.items as Array<{ name: string }>
-  return (
+  return !!(
     items?.length >= 2 &&
     items.find(item => item.name === 'game_minecraft') &&
     items.find(item => item.name === 'product_minecraft')

src/minecraft/api/mojang.ts

@@ -19,14 +19,16 @@ export const joinMinecraftSession = async (
   accessToken: string,
   selectedProfile: string,
   serverId: string
-) =>
+): Promise<Response> =>
   await fetch(joinMinecraftSessionUrl, {
     body: JSON.stringify({ accessToken, selectedProfile, serverId }),
     headers: { 'content-type': 'application/json' },
     method: 'POST'
   })
 
-export const getPlayerCertificates = async (accessToken: string) =>
+export const getPlayerCertificates = async (
+  accessToken: string
+): Promise<Certificate> =>
   await fetch(getPlayerCertificatesUrl, {
     headers: { Authorization: 'Bearer ' + accessToken },
     method: 'POST'

src/minecraft/api/yggdrasil.ts

@@ -51,7 +51,10 @@ export const refresh = async (
   return await request.json()
 }
 
-export const validate = async (accessToken: string, clientToken?: string) => {
+export const validate = async (
+  accessToken: string,
+  clientToken?: string
+): Promise<void> => {
   const request = await fetch('https://authserver.mojang.com/validate', {
     method: 'POST',
     headers: { 'content-type': 'application/json' },
@@ -64,7 +67,10 @@ export const validate = async (accessToken: string, clientToken?: string) => {
   }
 }
 
-export const signout = async (username: string, password: string) => {
+export const signout = async (
+  username: string,
+  password: string
+): Promise<void> => {
   const request = await fetch('https://authserver.mojang.com/signout', {
     method: 'POST',
     headers: { 'content-type': 'application/json' },
@@ -75,7 +81,10 @@ export const signout = async (username: string, password: string) => {
   }
 }
 
-export const invalidate = async (accessToken: string, clientToken: string) => {
+export const invalidate = async (
+  accessToken: string,
+  clientToken: string
+): Promise<void> => {
   const request = await fetch('https://authserver.mojang.com/invalidate', {
     method: 'POST',
     headers: { 'content-type': 'application/json' },

src/minecraft/chatToJsx.tsx

@@ -91,7 +91,7 @@ export interface HoverEvent {
   value: MinecraftChat
 }
 
-const hasColorCodes = (s: string) => /§[0-9a-fk-orx]/.test(s)
+const hasColorCodes = (s: string): boolean => /§[0-9a-fk-orx]/.test(s)
 // const stripColorCodes = (s: string) => s.replace(/§[0-9a-fk-orx]/g, '').trim()
 const parseColorCodes = (arg: string | PlainTextChat): PlainTextChat[] => {
   let s: string
@@ -253,7 +253,7 @@ const parseChatToJsx = (
   clickEventHandler: (clickEvent: ClickEvent) => void = () => {},
   componentProps?: Record<string, unknown>,
   trim = false
-) => {
+): JSX.Element => {
   let flat = sanitizeComponents(flattenComponents(chat))
   if (trim) flat = trimComponentsByLine(flat)
   return (
@@ -296,7 +296,7 @@ export const ChatToJsx = (props: {
   componentProps?: Record<string, unknown>
   clickEventHandler?: (clickEvent: ClickEvent) => void
   trim?: boolean
-}) =>
+}): JSX.Element =>
   parseChatToJsx(
     props.chat ?? { text: '' },
     props.component,
@@ -306,7 +306,7 @@ export const ChatToJsx = (props: {
     props.trim
   )
 
-export const parseValidJson = (text: string) => {
+export const parseValidJson = (text: string): any => {
   try {
     return JSON.parse(text)
   } catch (e) {

src/minecraft/connection/index.ts

@@ -37,7 +37,9 @@ export interface ServerConnection extends events.EventEmitter {
     ((event: string, listener: Function) => this) // eslint-disable-line @typescript-eslint/ban-types
 }
 
-const initiateConnection = async (opts: ConnectionOptions) => {
+const initiateConnection = async (
+  opts: ConnectionOptions
+): Promise<ServerConnection> => {
   if (isNativeConnectionAvailable()) {
     return await initiateNativeConnection(opts)
   }

src/minecraft/connection/javascript.ts

@@ -67,7 +67,7 @@ export class JavaScriptServerConnection
   }
 
   onlyOneCloseCall = false
-  close() {
+  close(): void {
     if (this.onlyOneCloseCall) return
     else this.onlyOneCloseCall = true
 
@@ -81,7 +81,9 @@ export class JavaScriptServerConnection
   }
 }
 
-const initiateJavaScriptConnection = async (opts: ConnectionOptions) => {
+const initiateJavaScriptConnection = async (
+  opts: ConnectionOptions
+): Promise<JavaScriptServerConnection> => {
   const [host, port] = await resolveHostname(opts.host, opts.port)
   const socket = net.createConnection({ host, port })
   const conn = new JavaScriptServerConnection(socket, opts)