useMqtt

Reactive mqtt-Client and -Subscriptions using MQTT.js.

Note: This is currenlty hardly more than a draft, use at your own risc and read the code to figure out what to do how.

Install

npm i @seiberspace/use-mqtt

# OR:
yarn add @seiberspace/use-mqtt

Usage

import { useMqtt, useSubscription } from '@seiberspace/use-mqtt';

// One time somewhere in your app:
useMqtt().create('wss://test.mosquitto.org:8081', {
  mapValue: (val) => val.toString(),
});

const { value } = useSubscription(topic, { default: '-' });

Example

<script>
import {
  defineComponent,
} from 'vue';

import {
  useMqtt,
  useSubscription,
} from '@seiberspace/use-mqtt';

//------------------------------------------------------------------------------
export default defineComponent({
  name: 'MqttValue',

  setup(props) {
    const {
      connected,
      error,
      create,
    } = useMqtt();
    const { value } = useSubscription('testtopic');

    create('wss://test.mosquitto.org:8081', {
      mapValue: (val) => val.toString(),
    });

    return {
      connected,
      value,
      error,
    };
  },
});
</script>

<template>
  <div>
    <div>Connected: {{connected}}</div>
    <div>Value: {{val}}</div>
    <div v-if="!!error">Error: {{error}}</div>
  </div>
</template>

Subscriptions are reference counted, useSubscription() hooks into the component's lifecycle. When the last reference is released, the client unsubscribes from that topic.

You can call useMqtt() as often as you like, it will always return the same instance. You can open() and close() the connection, and watch state for changes. Additionally there is an error which is set to the connection error, if any.

useMqtt() offers two convenience-computeds, connected and busy. busy is set to true while connecting or disconnecting.

create() is reentry-save (although ignoring changed parameters), and never fails. It reports errors via the error ref.

If you actually do need multiple MQTT-instances, you can do that: Check types.ts, you will figure it out.

TODO

A lot: Better typing, tests, full support of subscribe()-options and probably much more.