I am new to Typescript, and have recently begun a new React Native project where I'm running into an issue upon transpiling that causes the code to return this error in my simulator when running a build:
The issue seems to be stemming from using export default in Typescript to export my component (happens both with or without connection to the Redux store), which when transpired into plain js is identified as a parsing error. When using export without the default keyword and importing the deconstructed component it behaves as it should. Here is the .tsx file where it is exported:
import * as React from 'react';import { useState } from 'react';import { Button, StyleSheet, Text, TextInput, View } from 'react-native';import { ThunkDispatch } from 'redux-thunk';import { fetchUser } from '../store/actions/user';import { AppActions } from '../store/types';import { bindActionCreators } from 'redux';import { connect } from 'react-redux';import { User } from '../store/types/user';import { AppState } from '../store';interface Params { methodName: string; serviceName: string; params: string[];}interface ChildProps { setIsLoggedIn: any;}type Props = LinkDispatchProps & LinkStateProps & ChildProps;export const LoginWindow: React.FC<Props> = props => { const [userName, onChangeUserName] = useState<string>(''); const [pwd, onChangePwd] = useState<string>(''); const params: Params = { methodName: 'string1', serviceName: 'string2', params: [userName, pwd], }; const attemptLogin = async (): Promise<void> => { await props.fetchUser(params); if (props.user) { props.setIsLoggedIn(true); } }; return (<View><Text>Username:</Text><TextInput style={styles.textField} onChangeText={onChangeUserName} value={userName} textContentType="username" /><Text>Password:</Text><TextInput style={styles.textField} onChangeText={onChangePwd} value={pwd} textContentType="password" secureTextEntry={true} /><Button title="Log In" onPress={attemptLogin}> Log In</Button></View> );};const styles = StyleSheet.create({ textField: { height: 25, width: 200, borderStyle: 'solid', borderWidth: 1, borderColor: '#000', },});interface LinkStateProps { user: User;}interface LinkDispatchProps { fetchUser: (params: Params) => void;}const mapStateToProps = (state: AppState) => ({ user: state.user,});const mapDispatchToProps = ( dispatch: ThunkDispatch<any, any, AppActions>,): LinkDispatchProps => ({ fetchUser: bindActionCreators(fetchUser, dispatch),});export default connect(mapStateToProps, mapDispatchToProps)(LoginWindow);and here is where it is imported and used as a child component:
import * as React from 'react';import { useState } from 'react';import { SafeAreaView, ScrollView, StatusBar, // StyleSheet, Text, useColorScheme, View,} from 'react-native';import { Colors } from 'react-native/Libraries/NewAppScreen';import { connect } from 'react-redux';import { AppState } from '../store';import { User } from '../store/types/user';import LoginWindow from './LoginWindow';const App: React.FC = () => { const isDarkMode = useColorScheme() === 'dark'; const backgroundStyle = { backgroundColor: isDarkMode ? Colors.darker : Colors.lighter, }; const [isLoggedIn, setIsLoggedIn] = useState<boolean>(false); return (<SafeAreaView style={backgroundStyle}><StatusBar barStyle={isDarkMode ? 'light-content' : 'dark-content'} /><ScrollView contentInsetAdjustmentBehavior="automatic" style={backgroundStyle}> {isLoggedIn ? (<View style={{ backgroundColor: isDarkMode ? Colors.black : Colors.white, }}><Text>Log In Successful.</Text></View> ) : (<View style={{ backgroundColor: isDarkMode ? Colors.black : Colors.white, }}><LoginWindow setIsLoggedIn={setIsLoggedIn} /></View> )}</ScrollView></SafeAreaView> );};interface LinkStateProps { user: User;}const mapStateToProps = (state: AppState) => ({ user: state.user,});export default connect(mapStateToProps, null)(App);That transpiles into this:
"use strict";exports.__esModule = true;var React = require("react");var react_1 = require("react");var react_native_1 = require("react-native");var NewAppScreen_1 = require("react-native/Libraries/NewAppScreen");var react_redux_1 = require("react-redux");var LoginWindow_1 = require("./LoginWindow");var App = function () { var isDarkMode = react_native_1.useColorScheme() === 'dark'; var backgroundStyle = { backgroundColor: isDarkMode ? NewAppScreen_1.Colors.darker : NewAppScreen_1.Colors.lighter }; var _a = react_1.useState(false), isLoggedIn = _a[0], setIsLoggedIn = _a[1]; return (<react_native_1.SafeAreaView style={backgroundStyle}><react_native_1.StatusBar barStyle={isDarkMode ? 'light-content' : 'dark-content'}/><react_native_1.ScrollView contentInsetAdjustmentBehavior="automatic" style={backgroundStyle}> {isLoggedIn ? (<react_native_1.View style={{ backgroundColor: isDarkMode ? NewAppScreen_1.Colors.black : NewAppScreen_1.Colors.white }}><react_native_1.Text>Log In Successful.</react_native_1.Text></react_native_1.View>) : (<react_native_1.View style={{ backgroundColor: isDarkMode ? NewAppScreen_1.Colors.black : NewAppScreen_1.Colors.white }}><LoginWindow_1["default"] setIsLoggedIn={setIsLoggedIn}/></react_native_1.View>)}</react_native_1.ScrollView></react_native_1.SafeAreaView>);};var mapStateToProps = function (state) { return ({ user: state.user}); };exports["default"] = react_redux_1.connect(mapStateToProps, null)(App);It is my sense that <LoginWindow_1["default"] setIsLoggedIn={setIsLoggedIn}/> is what is causing my code to fail (and hovering over it reveals "Parsing Error, Unexpected Token" from VS Code), but I can't figure out why it behaves this way when transpiling. This is a brand new project using npx react-native init MyApp --template react-native-template-typescript with near default settings.
I have tried installing and configuring multiple dependencies:
@babel/plugin-transform-typescript @babel/preset-typescript @types/react @typescript-eslint/parser @typescript-eslint/eslint-pluginNone of which worked, so I removed them. Here is my package.json:
{"name": "reactmobile","version": "0.0.1","private": true,"scripts": {"android": "react-native run-android","ios": "react-native run-ios","start": "react-native start","test": "jest","lint": "eslint . --ext .js,.jsx,.ts,.tsx" },"dependencies": {"axios": "^0.21.1","react": "17.0.1","react-native": "0.64.1","react-redux": "^7.2.4","redux": "^4.1.0","redux-logger": "^3.0.6","redux-thunk": "^2.3.0" },"devDependencies": {"@babel/core": "^7.12.9","@babel/runtime": "^7.12.5","@react-native-community/eslint-config": "^2.0.0","@types/jest": "^26.0.23","@types/react-native": "^0.64.5","@types/react-test-renderer": "^16.9.2","@types/redux-logger": "^3.0.9","babel-jest": "^26.6.3","eslint": "^7.30.0","jest": "^26.6.3","metro-react-native-babel-preset": "^0.64.0","react-native-typescript-transformer": "^1.2.13","react-test-renderer": "17.0.1","typescript": "^4.3.5" },"resolutions": {"@types/react": "^17" },"jest": {"preset": "react-native","moduleFileExtensions": ["ts","tsx","js","jsx","json","node" ] }}tsconfig.json:
{"compilerOptions": { /* Basic Options */"target": "esnext", /* Specify ECMAScript target version: 'ES3' (default), 'ES5', 'ES2015', 'ES2016', 'ES2017','ES2018' or 'ESNEXT'. */"module": "commonjs", /* Specify module code generation: 'none', 'commonjs', 'amd', 'system', 'umd', 'es2015', or 'ESNext'. */"lib": ["es2017"], /* Specify library files to be included in the compilation. */"allowJs": true, /* Allow javascript files to be compiled. */ // "checkJs": true, /* Report errors in .js files. */"jsx": "react-native", /* Specify JSX code generation: 'preserve', 'react-native', or 'react'. */ // "declaration": true, /* Generates corresponding '.d.ts' file. */"sourceMap": true, /* Generates corresponding '.map' file. */ // "outFile": "./", /* Concatenate and emit output to single file. */ // "outDir": "./", /* Redirect output structure to the directory. */ // "rootDir": "./", /* Specify the root directory of input files. Use to control the output directory structure with --outDir. */ // "removeComments": true, /* Do not emit comments to output. */"noEmit": true, /* Do not emit outputs. */ // "incremental": true, /* Enable incremental compilation */ // "importHelpers": true, /* Import emit helpers from 'tslib'. */ // "downlevelIteration": true, /* Provide full support for iterables in 'for-of', spread, and destructuring when targeting 'ES5' or 'ES3'. */"isolatedModules": true, /* Transpile each file as a separate module (similar to 'ts.transpileModule'). */ /* Strict Type-Checking Options */"strict": true, /* Enable all strict type-checking options. */ // "noImplicitAny": true, /* Raise error on expressions and declarations with an implied 'any' type. */ // "strictNullChecks": true, /* Enable strict null checks. */ // "strictFunctionTypes": true, /* Enable strict checking of function types. */ // "strictPropertyInitialization": true, /* Enable strict checking of property initialization in classes. */ // "noImplicitThis": true, /* Raise error on 'this' expressions with an implied 'any' type. */ // "alwaysStrict": true, /* Parse in strict mode and emit "use strict" for each source file. */ /* Additional Checks */ // "noUnusedLocals": true, /* Report errors on unused locals. */ // "noUnusedParameters": true, /* Report errors on unused parameters. */ // "noImplicitReturns": true, /* Report error when not all code paths in function return a value. */ // "noFallthroughCasesInSwitch": true, /* Report errors for fallthrough cases in switch statement. */ /* Module Resolution Options */"moduleResolution": "node", /* Specify module resolution strategy: 'node' (Node.js) or 'classic' (TypeScript pre-1.6). */ // "baseUrl": "./", /* Base directory to resolve non-absolute module names. */ // "paths": {}, /* A series of entries which re-map imports to lookup locations relative to the 'baseUrl'. */ // "rootDirs": [], /* List of root folders whose combined content represents the structure of the project at runtime. */ // "typeRoots": [], /* List of folders to include type definitions from. */ // "types": [], /* Type declaration files to be included in compilation. */"allowSyntheticDefaultImports": true, /* Allow default imports from modules with no default export. This does not affect code emit, just typechecking. */"esModuleInterop": true, /* Enables emit interoperability between CommonJS and ES Modules via creation of namespace objects for all imports. Implies 'allowSyntheticDefaultImports'. */ // "preserveSymlinks": true, /* Do not resolve the real path of symlinks. */"skipLibCheck": true, /* Skip type checking of declaration files. */ /* Source Map Options */ // "sourceRoot": "./", /* Specify the location where debugger should locate TypeScript files instead of source locations. */ // "mapRoot": "./", /* Specify the location where debugger should locate map files instead of generated locations. */ // "inlineSourceMap": true, /* Emit a single file with source maps instead of having a separate file. */ // "inlineSources": true, /* Emit the source alongside the sourcemaps within a single file; requires '--inlineSourceMap' or '--sourceMap' to be set. */ /* Experimental Options */ // "experimentalDecorators": true, /* Enables experimental support for ES7 decorators. */ // "emitDecoratorMetadata": true, /* Enables experimental support for emitting type metadata for decorators. */ },"include": ["./src/**/*.tsx","./src/**/*.ts"],"exclude": ["node_modules", "babel.config.js", "metro.config.js", "jest.config.js" ]}babel.config.js:
module.exports = { presets: ['module:metro-react-native-babel-preset'],};