React Native Alert.alert() only works on iOS and Android not web

Question

I just started learning and practicing React Native and I have run into the first problem that I cant seem to solve by myself.

I have the following code, which is very simple, but the Alert.alert() does not work when I run it on the web. if I click the button nothing happens, however, when i click the button on an iOS or android simulator it works fine.

import { StatusBar } from 'expo-status-bar';
import React from 'react';
import { StyleSheet, Text, Button, View, Alert } from 'react-native';

export default function App() {
  return (
      <View style={styles.container}>
        <Text style={styles.headerStyle} >Practice App</Text>
        <Text style={{padding: 10}}>Open up App.js to start working on your app!</Text>
        <Button
          onPress={() => alert('Hello, Nice To Meet You  :)')}
          title="Greet Me"
        />
        <StatusBar style="auto" />
      </View>
  );
}

I also know that alert() works on all three devices, however, I want to understand why Alert.alert() only works for iOS and Android.

My question is more so for understanding rather than finding a solution. Is the only solution to use alert(), or am I implementing Alert.alert() in the wrong way?

Answer 1

React Native is an open-source mobile application framework for Android, iOS and Web but there is not an Alert Component for Web but I have found a package which will provide you solutation. That is it to install package

npm i react-native-awesome-alerts

This example will help you

import React from "react";
import { StyleSheet, Text, View, TouchableOpacity } from "react-native";
import Alert from "react-native-awesome-alerts";
export default class App extends React.Component {
  constructor(props) {
    super(props);
    this.state = { showAlert: false };
  }

  showAlert = () => {
    this.setState({
      showAlert: true,
    });
  };

  hideAlert = () => {
    this.setState({
      showAlert: false,
    });
  };

  render() {
    const { showAlert } = this.state;

    return (
      <View style={styles.container}>
        <Text>Practice App</Text>
        <Text style={{ padding: 10 }}>
          Open up App.js to start working on your app!
        </Text>
        <TouchableOpacity
          onPress={() => {
            this.showAlert();
          }}
        >
          <View style={styles.button}>
            <Text style={styles.text}>Greet Me</Text>
          </View>
        </TouchableOpacity>

        <Alert
          show={showAlert}
          message="Hello, Nice To Meet You  :"
          closeOnTouchOutside={true}
        />
      </View>
    );
  }
}

const styles = StyleSheet.create({
  container: {
    flex: 1,
    alignItems: "center",
    justifyContent: "center",
    backgroundColor: "#fff",
  },
  button: {
    margin: 10,
    paddingHorizontal: 10,
    paddingVertical: 7,
    borderRadius: 5,
    backgroundColor: "#AEDEF4",
  },
  text: {
    color: "#fff",
    fontSize: 15,
  },
});

Answer 2

This workaround basically imitates react-native 's Alert behavior with browsers' window.confirm method:

# alert.js
import { Alert, Platform } from 'react-native'

const alertPolyfill = (title, description, options, extra) => {
    const result = window.confirm([title, description].filter(Boolean).join('\n'))

    if (result) {
        const confirmOption = options.find(({ style }) => style !== 'cancel')
        confirmOption && confirmOption.onPress()
    } else {
        const cancelOption = options.find(({ style }) => style === 'cancel')
        cancelOption && cancelOption.onPress()
    }
}

const alert = Platform.OS === 'web' ? alertPolyfill : Alert.alert

export default alert

Usage:

Before:

import { Alert } from 'react-native'
Alert.alert(...)

After:

import alert from './alert'
alert(...)

Source & Credits: https://github.com/necolas/react-native-web/issues/1026#issuecomment-679102691