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React Native Initialization Example

  • I am having trouble getting a basic client. Can someone post a basic running app with initialization? I get failure when instantiating colyseus (new Colyseus.Client(...))

  • administrators

    Hey @merhawie, do you mind posting the error you’re having? Stack traces and logs would be helpful to help you out. Cheers

  • The text of the error that I get is the following:

    undefined is not an object (evaluating 'storage.getItem')

    getItem (Storage.js:11:24)
    Client (Client.js:22:26)
    <unknown> (App.js:25:33)

    This last line references code outside of the class definition (but the same thing occurs if initialized in the constructor), the line reads: var client = new Colyseus.Client(endpoint);

    Does this help? Do I need to provide a screenshot?

  • administrators

    I see @merhawie, have you followed the caveats for React Native compatibility here?

    Looks like you're missing this:

    import { AsyncStorage } from 'react-native';
    window.localStorage = AsyncStorage;


  • @endel - thank you for the quick response! Here is my App.js import stack:

    import 'react-native-browser-polyfill';
    import React, {Component} from 'react';
    import {Platform, StyleSheet, Text, View, AsyncStorage} from 'react-native';
    //Necessary libraries for Colyseus
    window.localStorage = AsyncStorage;
    import Colyseus from "colyseus.js";

    Below is a screenshot of the actual error I am receiving:
    0_1531526246043_Simulator Screen Shot - iPhone 6 - 2018-07-13 at 16.56.50.png

  • administrators

    Hey @merhawie, I see, managed to reproduce the issue using react-native 0.56.0, is this the version you're using as well?

    It seems react-native is importing colyseus.js before assigned AsyncStorage to window (even though the import order is correct), and that is causing the problem. 😢

    I suspect that's because Babel 7 moves all imports before any other code execution (like window.localStorage = ...)

    I'd appreciate if you could come up with a solution for this! I've just created an issue on GitHub about this.

    Cheers, thanks for reporting.

  • administrators

    Sorry @merhawie, that was actually my bad.

    I've managed to fix this on version 0.9.11 of the client. During some refactoring on the client, I've moved the Storage to a different file and forgot that the storage should not have been assigned upon module loading.

    It works fine now!