# SASL

SASL Negotiation for `@xmpp/client`.

Included and enabled in `@xmpp/client`.

## Usage

### object

```js
const {xmpp} = require('@xmpp/client')
const client = xmpp({credentials: {
  username: 'foo',
  password: 'bar'
})
```

### function

Instead, you can provide a function that will be called every time authentication occurs (every (re)connect).

Uses cases:

- Have the user enter the password every time
- Do not ask for password before connection is made
- Debug authentication
- Using a SASL mechanism with specific requirements
- Perform an asynchronous operation to get credentials

```js
const { xmpp } = require("@xmpp/client");
const client = xmpp({ credentials: authenticate });

async function authenticate(auth, mechanism) {
  console.debug("authenticate", mechanism);
  const credentials = {
    username: await prompt("enter username"),
    password: await prompt("enter password"),
  };
  console.debug("authenticating");
  try {
    await auth(credentials);
    console.debug("authenticated");
  } catch (err) {
    console.error(err);
    throw err;
  }
}
```

## References

[RFC 6120 SASL Negotiation](https://xmpp.org/rfcs/rfc6120.html#sasl)