---
sidebar_position: 2
title: User Login Function
slug: RnOw-user-login-function
createdAt: Fri Jul 19 2024 03:45:40 GMT+0000 (Coordinated Universal Time)
updatedAt: Fri Jul 19 2024 03:56:00 GMT+0000 (Coordinated Universal Time)
---

# User Login Function

This documentation provides a detailed explanation of the `login` function, which handles user login in an asynchronous manner, including checks for user authentication, showing loading indicators, and emitting events upon successful login.

## Function: `login`

### Description

The `login` function is designed to check if a user is logged in, and if not, it will attempt to log the user in by repeatedly checking for owned users. It uses asynchronous operations to ensure the login process is smooth and non-blocking.

### Code

```javascript
async function login() {
	try {
		let time = new Date().getTime();
		console.log(`demo index login start time = ${time}`);
		let user = new User();
		let temp = await user.islogin();
		console.log(`demo index islogin end time = ${time}, temp = ${temp}`);
		if (!temp) {
			showLoadingToast({
				duration: 0,
				forbidClick: true,
				message: 'Loading...',
			});
			console.log(`demo index showLoadingToast end time = ${time}`);
			for (let i = 0; i < 5; i++) {
				let result = await user.getOwnedUsers();
				let userid = result && result._userIds && result._userIds.length && result._userIds[0];
				if (userid && userid.length) {
					break;
				}
				await sleep(300);
			}
			closeToast();
			temp = await user.islogin();
			if (!temp) {
				showToast("login failed, please try again later");
				return;
			}
		}
		bus.emit('get_balance', "login");
		console.log(`demo index login end time = ${new Date().getTime() - time}`);
	} catch (error) {
		console.log("index demo error", error);
		closeToast();
		if (error && typeof error == 'string') {
			showToast(error);
		} else {
			showToast(error.message);
		}
	} finally {
	}
}

onMounted(() => {
	getTemplateList();
	login();
});
```

### Detailed Explanation

1. **Initialization and Logging Start Time:**
   - Records the start time for login.
   - Logs the start time to the console.
2. **User Object and Initial Login Check:**
   - Creates a new `User` object.
   - Checks if the user is already logged in by calling `user.islogin()` and logs the result.
3. **Show Loading Indicator:**
   - If the user is not logged in, shows a loading toast to inform the user that a login attempt is in progress.
4. **Repeated Attempts to Get Owned Users:**
   - Attempts to get the list of owned users up to 5 times, with a 300ms delay between each attempt.
   - Breaks the loop if a valid user ID is found.
5. **Close Toast and Final Login Check:**
   - Closes the loading toast.
   - Checks the login status again. If still not logged in, shows an error toast and exits the function.
6. **Emit Event and Log End Time:**
   - Emits an event to get the balance.
   - Logs the end time to the console.
7. **Error Handling:**
   - Catches any errors that occur during the login process.
   - Logs the error to the console.
   - Closes the toast and shows an appropriate error message to the user.

## Usage in Component Lifecycle

The `login` function is called within the `onMounted` lifecycle hook, ensuring that the login process is initiated when the component is mounted.

```javascript
onMounted(() => {
	login();
});
```

- `getTemplateList()`: Fetches the list of templates (additional context not provided in the snippet).
- `login()`: Initiates the login process.

This setup ensures that the user login status is checked and handled as soon as the component is ready, providing a seamless experience for the user.
