React Native DEV and PROD variables

-

How do I know if my React Native app is running in production or development? Is there some sort of way within JavaScript to tell? Is there a global that is passed in?

You can use the __DEV__ global variable in JavaScript to determine if you're using React Native packager or not. If you are running your app in the iOS Simulator or Android emulator __DEV__ will be set to true.

https://facebook.github.io/react-native/docs/javascript-environment.html

Comments

Post a Comment

Popular posts from this blog

Meaning of `{}` for return expression

-
15 1 I found by accident that the following compiles: #include <string> #include <iostream> class A{ int i{}; std::string s{}; public: A(int _i, const std::string& _s) : i(_i), s(_s) { puts("Called A(int, const std::string)"); } }; A foo(int k, const char* cstr){ return {k, cstr}; // (*) } int main(){ auto a = foo(10, "Hi!"); return 0; } The line of interest is (*). I guess the function foo is equivalent to: A foo(int k, const char* str){ return A(k, cstr); } However, is there a special name for this mechanism in (*)? Or is it just the simple fact that the compiler knows which constructor to call due to the return type? ...
Read more

Get current scroll position of ScrollView in React Native

-
Is it possible to get the current scroll position, or the current page of a <ScrollView> component in React Native? So something like: <ScrollView horizontal={true} pagingEnabled={true} onScrollAnimationEnd={() => { // get this scrollview's current page or x/y scroll position }}> this.state.data.map(function(e, i) { <ImageCt key={i}></ImageCt> }) </ScrollView> Try. <ScrollView onScroll={this.handleScroll} /> And then: handleScroll: function(event: Object) { console.log(event.nativeEvent.contentOffset.y); }, Disclaimer: what follows is primarily the result of my own experimentation in React Native 0.50. The ScrollView documentation is currently missing a lot of the information covered below; for instance onScrollEndDrag is completely undocumented. Since everything here relies upon undocumented behaviour, I can unfortunately make no promises that this information will remain correct a ...
Read more

flutter websocket connection issue

-
I am trying to develop a flutter app which connects to the server and exchanges data using websocket. The server is in .Net Core and using Asp.Net Core Websockets to implement this functionality. The problem I am facing is, my flutter app is not able to connect to the server and throws following error. E/flutter (31498): [ERROR:topaz/lib/tonic/logging/dart_error.cc(16)] Unhandled exception: E/flutter (31498): WebSocketChannelException: WebSocketChannelException: WebSocketException: Connection to 'http://127.0.0.1/client#' was not upgraded to websocket E/flutter (31498): #0 new IOWebSocketChannel._withoutSocket.<anonymous closure> (package:web_socket_channel/io.dart:83:24) E/flutter (31498): #1 _invokeErrorHandler (dart:async/async_error.dart:13:29) E/flutter (31498): #2 _HandleErrorStream._handleError (dart:async/stream_pipe.dart:286:9) E/flutter (31498): #3 _ForwardingStreamSubscription._handleError (dart:async/stream_pipe.dart:168:13) E/flutter (3149...
Read more