client-state

Manage event-emitting clients using a state machine.

install

npm install client-state

Usage

The goal is to provide a Finite State Machine that reflects various states of availability for a given endpoint or service (which I will call a client, such as a Redis database.

An instance of this module's interface emits events corresponding to events in the client.

For example, assume that a client emits the following events:

• connect (a connection has been established)
• ready (the connection is ready to receive commands)
• reconnecting
• end (a connection has been lost)
• error (some sort of error with the connection has occurred)
• warning (some non-critical warning has been emitted by the client)

If you pass this client to client-state:

let cs = require('client-state');
let stateM = cs(someclient);

You can query the current state of the client like so:

stateM.state() // `ready`, for example

You can listen for state changes (again, reflecting events emitted by client)

stateM.on('ready', data => {
    // See below for breakdown of what `data` is
});

The redis module emits all of the above events.