Build a login form with React
In this section, we create a custom login form with email/username and password that includes:
- Email or username field
- Error messages
- Single sign-on (SSO) with Google
#Example: custom login form with React
You can clone the example login form on CodePen(opens new window) and make edits, or follow along below.
The example form has the Userfront Core JS library added to the document, as described in the next section.
#Add the Userfront Core JS library
You can add the Userfront Core JS library by CDN or using npm.
You only need to do one of these.
#Set up the form
Create your login form with the elements you want to use.
In this case, we've added:
emailOrUsername
- the user's email address or usernamepassword
- required for login with password
#Login form React code
#constructor()
Here we set up our state variables with emailOrUsername
and password
.
We also bind our functions so that this.setState
will update the state variables.
#handleInputChange()
Whenever an input changes value, this function will set the corresponding state variable.
#handleSubmit()
When the form is submitted, this function will call Userfront.login()
with the current emailOrUsername
and password
.
#render()
Adds the login form with 2 inputs and a button, and connects them to the handleInputChange()
and handleSubmit()
functions.
#Email or username field
For login, you can use the emailOrUsername
field, which will accept both email and username.
If you want email only, or username only, you can use the email
or username
attributes instead of emailOrUsername
.
#Error handling
Whenever the Userfront.login()
method fails, we can catch
its error in the promise chain.
This error contains a message
property with what went wrong.
In this example, we use an <Alert />
component to display the error message.
Our login form can use this component by including an alertMessage
variable in the state, and then setting it whenever we want to update the message.
Now the handleSubmit()
method clears the alert message whenever the button is clicked. Then if there is an error with Userfront.login()
, it catches the error and displays the error message.
The alert component is rendered above the form as:
<Alert message={this.state.alertMessage} />
#Single sign-on
To configure Single sign-on (SSO), first add the provider you want to use in the Userfront dashboard in the SSO tab.
In this example, we add an <SSOButton />
component to allow login with Google.
Ultimately, we need to call Userfront.login({ method: "google" })
whenever the button is clicked. You can style the button however you like.
You can find more provider options like GitHub, LinkedIn, and Facebook in the docs for login().
To render the <SSOButton />
component into the login form, we can add it below the <form>
element.
#Login after redirect
Once the browser is redirected back to your login page after SSO approval, your application should call
Userfront.login({ method: "link" })
You can set up your JS to call this method automatically by checking whether the URL contains the token
and uuid
parameters.
If your original SSO signup call contained a redirect
parameter, it will be included in the URL and followed automatically.