@react-native-school/expo-typescript-template/src/util/auth.ts

A simple Expo template with navigation, testing, and linting setup.

import React, { Dispatch, SetStateAction } from 'react';
import { Alert } from 'react-native';

type ErrorType = {
  email?: string;
  password?: string;
};

export const useLogin = () => {
  const [email, setEmail] = React.useState('');
  const [password, setPassword] = React.useState('');
  const [errors, setErrors]: [
    ErrorType,
    Dispatch<SetStateAction<{}>>,
  ] = React.useState({});

  const submit = () => {
    const nextErrors: ErrorType = {};
    if (email.length === 0) {
      nextErrors.email = 'This field is required.';
    }
    if (password.length === 0) {
      nextErrors.password = 'This field is required.';
    }
    setErrors(nextErrors);

    if (Object.keys(nextErrors).length > 0) {
      return null;
    }

    Alert.alert('Success!', `Email: ${email} \n Password: ${password}`);
    return null;
  };

  return {
    submit,
    errors,
    email,
    setEmail,
    password,
    setPassword,
  };
};