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Create a login form
In this chapter, you will learn how to
- Sign in using username and password
- Display data of an authenticated user
- Display authentication errors
- Logout
Build the form
Let us start by providing some reactive objects and input elements to get customer login credentials from the browser.
vue
<script setup lang="ts">
const loginCredentials = reactive({
username: "",
password: "",
})
const invokeLogin = () => {}
</script>
<template>
<div>
<input type="text" v-model="loginCredentials.username" />
<input type="password" v-model="loginCredentials.password" />
<button @click="invokeLogin">Sign in</button>
</div>
</template>
Manage the user session
Now, the presentation layer has all required fields to perform a login process.
In the next step, use the useUser
composable. It provides user data, login methods, and other interfaces.
vue
<script setup lang="ts">
const {
login, // login method, accepts username and password
logout, // performing a logout
errors, // errors from API prefixed with a method name, which is the source of the problem
isLoggedIn, // flag that says if customer is logged in
user, // the whole customer object
} = useUser();
const invokeLogin = () => login(loginCredentials);
</script>
...
The invokeLogin
method is triggered using the @click
event of the button. It executes the login()
method from the useUser
composable, accepting loginCredentials
(the v-model
of inputs) as an argument.
Display user data
If the login process was successful, the isLoggedIn
computed property becomes true
. Now we can use user
object to access customer data.
vue
<template>
<div v-if="!isLoggedIn">
<!-- DISPLAY FORM HERE -->
</div>
<div v-else>
<h1>Hi, {{ user.firstName }}!</h1>
<button @click="logout()">sign out</button>
</div>
</template>
The example above shows the conditional visibility of content depending on the customer's logged in state.
Handle authentication errors
To finish, we would like to inform the user about problems that may appear during the authentication.
In order to achieve it, the errors
computed ref can be used:
vue
<template>
<div v-if="!isLoggedIn">
<div v-if="errors.login.length">
{{ errors.login[0].detail }}
</div>
</div>
</template>
The example explains how to display only the first error that may appear in the response while processing the login
method (see, the errors
computed has prefixed login
nested object).
Full example
vue
<script setup lang="ts">
const { logout, login, errors, isLoggedIn, user } = useUser();
const loginCredentials = reactive({
username: "",
password: "",
});
const invokeLogin = () => login(loginCredentials);
</script>
<template>
<div v-if="!isLoggedIn">
<h1>Sign in to your account</h1>
<input type="text" v-model="loginCredentials.username" />
<input type="password" v-model="loginCredentials.password" />
<button @click="invokeLogin">sign in</button>
<div v-if="errors.login.length">
{{ errors.login[0].detail }}
</div>
</div>
<div v-else>
<h1>Hi, {{ user.firstName }}!</h1>
<button @click="logout()">sign out</button>
</div>
</template>
<style scoped>
.errors {
color: red;
margin-top: 10px;
}
</style>