Current User
6 min
Get current User for React
Introduction
After implementing user registration and login to your, you need to retrieve the currently logged user data to perform different actions and requests. This data can be promptly retrieved by using Parse.User.current inside your app components.
Prerequisites
To complete this tutorial, you will need:
- Complete the previous guide so you can have a better understanding of the Parse.User class and the Parse.User.logIn method
- If you want to test/use the screen layout provided by this guide, you should set up the Ant Design library.
Goal
Get the current user data fetching using Parse for a React app.
1 - Retrieving Current User
The method Parse.User.current can be used anywhere on your code, after properly configuring your app to use Parse. Its response will be your current user’s object (Parse.User) or null if there is no logged-in user currently.
1 const getCurrentUser = async function (): Promise<Parse.User | null> {
2 const currentUser: Parse.User = await Parse.User.current();
3 if (currentUser !== null) {
4 Alert.alert(
5 'Success!',
6 `${currentUser.get('username')} is the current user!`,
7 );
8 }
9 return currentUser;
10 };This method is essential in situations where you don’t have access to your application state or your user data, making it possible to perform relevant Parse requests in any component of your app.
2 - Using Current User in a React component
In our previous guides, the Parse.User.current method was already used for testing showing the current username on the User Login guide. Here is the UserLogin component code, take a closer look at the getCurrentUser function:
1 import React, { useState, FC, ReactElement } from 'react';
2 import './App.css';
3 import { Button, Divider, Input } from 'antd';
4 const Parse = require('parse/dist/parse.min.js');
5
6 export const UserLogin: FC<{}> = (): ReactElement => {
7 // State variables
8 const [username, setUsername] = useState('');
9 const [password, setPassword] = useState('');
10 const [currentUser, setCurrentUser] = useState<Parse.Object | null>(null);
11
12 const doUserLogIn = async function (): Promise<boolean> {
13 // Note that these values come from state variables that we've declared before
14 const usernameValue: string = username;
15 const passwordValue: string = password;
16 try {
17 const loggedInUser: Parse.User = await Parse.User.logIn(usernameValue, passwordValue);
18 // logIn returns the corresponding ParseUser object
19 alert(
20 `Success! User ${loggedInUser.get('username')} has successfully signed in!`,
21 );
22 // To verify that this is in fact the current user, `current` can be used
23 const currentUser: Parse.User = await Parse.User.current();
24 console.log(loggedInUser === currentUser);
25 // Clear input fields
26 setUsername('');
27 setPassword('');
28 // Update state variable holding current user
29 getCurrentUser();
30 return true;
31 } catch (error: any) {
32 // Error can be caused by wrong parameters or lack of Internet connection
33 alert(`Error! ${error.message}`);
34 return false;
35 }
36 };
37
38 const doUserLogOut = async function (): Promise<boolean> {
39 try {
40 await Parse.User.logOut();
41 // To verify that current user is now empty, currentAsync can be used
42 const currentUser: Parse.User = await Parse.User.current();
43 if (currentUser === null) {
44 alert('Success! No user is logged in anymore!');
45 }
46 // Update state variable holding current user
47 getCurrentUser();
48 return true;
49 } catch (error: any) {
50 alert(`Error! ${error.message}`);
51 return false;
52 }
53 };
54
55 // Function that will return current user and also update current username
56 const getCurrentUser = async function (): Promise<Parse.User | null> {
57 const currentUser: (Parse.User | null) = await Parse.User.current();
58 // Update state variable holding current user
59 setCurrentUser(currentUser);
60 return currentUser;
61 }
62
63 return (
64 <div>
65 <div className="header">
66 <img
67 className="header_logo"
68 alt="Back4App Logo"
69 src={
70 'https://blog.back4app.com/wp-content/uploads/2019/05/back4app-white-logo-500px.png'
71 }
72 />
73 <p className="header_text_bold">{'React on Back4App'}</p>
74 <p className="header_text">{'User Login'}</p>
75 </div>
76 {currentUser === null &&
77 (<div className="container">
78 <h2 className="heading">{'User Login'}</h2>
79 <Divider />
80 <div className="form_wrapper">
81 <Input
82 value={username}
83 onChange={(event) => setUsername(event.target.value)}
84 placeholder="Username"
85 size="large"
86 className="form_input"
87 />
88 <Input
89 value={password}
90 onChange={(event) => setPassword(event.target.value)}
91 placeholder="Password"
92 size="large"
93 type="password"
94 className="form_input"
95 />
96 </div>
97 <div className="form_buttons">
98 <Button
99 onClick={() => doUserLogIn()}
100 type="primary"
101 className="form_button"
102 color={'#208AEC'}
103 size="large"
104 >
105 Log In
106 </Button>
107 </div>
108 </div>)
109 }
110 {currentUser !== null &&
111 (<div className="container">
112 <h2 className="heading">{'User Screen'}</h2>
113 <Divider />
114 <h2 className="heading">{`Hello ${currentUser.get('username')}!`}</h2>
115 <div className="form_buttons">
116 <Button
117 onClick={() => doUserLogOut()}
118 type="primary"
119 className="form_button"
120 color={'#208AEC'}
121 size="large"
122 >
123 Log Out
124 </Button>
125 </div>
126 </div>)
127 }
128 </div>
129 );
130 };In this component, the Parse.User.current method retrieves the username and updates the state variable that is rendered inside the component JSX. Add these classes to your App.css file to fully render the layout styles:
1 @import '~antd/dist/antd.css';
2
3 .App {
4 text-align: center;
5 }
6
7 html {
8 box-sizing: border-box;
9 outline: none;
10 overflow: auto;
11 }
12
13 *,
14 *:before,
15 *:after {
16 margin: 0;
17 padding: 0;
18 box-sizing: inherit;
19 }
20
21 h1,
22 h2,
23 h3,
24 h4,
25 h5,
26 h6 {
27 margin: 0;
28 font-weight: bold;
29 }
30
31 p {
32 margin: 0;
33 }
34
35 body {
36 margin: 0;
37 background-color: #fff;
38 }
39
40 .container {
41 width: 100%;
42 max-width: 900px;
43 margin: auto;
44 padding: 20px 0;
45 text-align: left;
46 }
47
48 .header {
49 align-items: center;
50 padding: 25px 0;
51 background-color: #208AEC;
52 }
53
54 .header_logo {
55 height: 55px;
56 margin-bottom: 20px;
57 object-fit: contain;
58 }
59
60 .header_text_bold {
61 margin-bottom: 3px;
62 color: rgba(255, 255, 255, 0.9);
63 font-size: 16px;
64 font-weight: bold;
65 }
66
67 .header_text {
68 color: rgba(255, 255, 255, 0.9);
69 font-size: 15px;
70 }
71
72 .heading {
73 font-size: 22px;
74 }
75
76 .flex {
77 display: flex;
78 }
79
80 .flex_between {
81 display: flex;
82 justify-content: space-between;
83 }
84
85 .flex_child {
86 flex: 0 0 45%;
87 }
88
89 .heading_button {
90 margin-left: 12px;
91 }
92
93 .list_item {
94 padding-bottom: 15px;
95 margin-bottom: 15px;
96 border-bottom: 1px solid rgba(0,0,0,0.06);
97 text-align: left;
98 }
99
100 .list_item_title {
101 color: rgba(0,0,0,0.87);
102 font-size: 17px;
103 }
104
105 .list_item_description {
106 color: rgba(0,0,0,0.5);
107 font-size: 15px;
108 }Conclusion
At the end of this guide, you learned how to retrieve the current Parse user data from local storage on React. In the next guide, we will show you how to enable your user to reset his password.