sdk-base

A base class for sdk with some common & useful functions.

Installation

npm install sdk-base

Usage

Constructor argument:

• {Object} options

  • {String} [initMethod] - the async init method name, the method should be a function return promise. If set, will execute the function in the constructor.
  • {AsyncLocalStorage} [localStorage] - async localStorage instance.

  const { Base } = require('sdk-base');
  
  class Client extends Base {
    constructor() {
      super({
        initMethod: 'init',
        localStorage: app.ctxStorage,
      });
    }
  
    async init() {
      // put your async init logic here
    }
    // support async function too
    // async init() {
    //   // put your async init logic here
    // }
  }
  
  (async function main() {
    const client = new Client();
    // wait client ready, if init failed, client will throw an error.
    await client.ready();
  
    // support async event listener
    client.on('data', async function (data) {
      // put your async process logic here
      //
      // @example
      // ----------
      // await submit(data);
    });
  
    client.emit('data', { foo: 'bar' });
  
  })().catch(err => { console.error(err); });

API

• .ready(flagOrFunction) flagOrFunction is optional, and the argument type can be Boolean, Error or Function.

  // init ready
  client.ready(true);
  // init failed
  client.ready(new Error('init failed'));
  
  // listen client ready
  client.ready(err => {
    if (err) {
      console.log('client init failed');
      console.error(err);
      return;
    }
    console.log('client is ready');
  });
  
  // support promise style call
  client.ready()
    .then(() => { ... })
    .catch(err => { ... });
  
  // support async function style call
  await client.ready();

• async readyOrTimeout(milliseconds) ready or timeout, after milliseconds not ready will throw TimeoutError

  await client.readyOrTimeout(100);

• .isReady getter detect client start ready or not.

• .on(event, listener) wrap the EventEmitter.prototype.on(event, listener), the only difference is to support adding async function listener on events, except 'error' event.

• once(event, listener) wrap the EventEmitter.prototype.once(event, listener), the only difference is to support adding async function listener on events, except 'error' event.

• prependListener(event, listener) wrap the EventEmitter.prototype.prependListener(event, listener), the only difference is to support adding async function listener on events, except 'error' event.

• prependOnceListener(event, listener) wrap the EventEmitter.prototype.prependOnceListener(event, listener), the only difference is to support adding generator listener on events, except 'error' event.

• addListener(event, listener) wrap the EventEmitter.prototype.addListener(event, listener), the only difference is to support adding async function listener on events, except 'error' event.

  client.on('data', async function(data) {
    // your async process logic here
  });
  client.once('foo', async function(bar) {
    // ...
  });
  
  // listen error event
  client.on('error', err => {
    console.error(err.stack);
  });

• .await(event): await an event, return a promise, and it will resolve(reject if event is error) once this event emmited.

  const data = await client.await('data');

• ._close(): The _close() method is called by close. It can be overridden by child class, but should not be called directly. It must return promise or generator.

• .close(): The close() method is used to close the instance.

Breaking changes between v4 and v5

• Drop .awaitFirst(events) support
• Drop generator function support
• Don't catch event listener inside error

License

MIT

Contributors

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