Adding Typescript typings.

[saboya]

Finishing the Typescript typings spree, following mqttjs/mqtt-packet#39.

Unfortunately aedes needs export assignment, which limits the usage of the typinngs somewhat, but it's still very helpful.

[mcollina]

Can you add a unit test for the typings? Something that gets transpiled correctly. Something like https://github.com/mqttjs/MQTT.js/tree/master/test/typescript

[mcollina]

I prefer @types/node to be a devDependency.

[saboya]

You're right, that's my bad.

[saboya]

I adjusted the @types/node dependency and adjusted / added more typings. There are some issues with the typings though:

Like I said, aedes requires export assignment because it exports a function directly. This effectively prevents any other exports, which means that anything defined inside those typings cannot be referenced. This is not an issue for implicit typing, but prevents explicit typing.

Some cases where this might be an issue:

Return Error with returnCode set:

import Aedes = require('aedes')

const authCallback: ,

const Aedes = Aedes({
  authenticate: (client, username: string, password: string, callback) => {
    if (username === 'test' && password === 'test') {
      callback(null, true)
    } else {
      // returnCode is not a property of Error, so this is the
      // only way to fulfill the desired interface from outside
      const error = new Error() as Error & { returnCode: number }
      error.returnCode = 1

      callback(error, false)
    }
  }
})

Indirect assignment of functions that use non-exported definitions:

// Since we cannot reference Client our AuthCallback, we can't define them properly
const authCallback = (client: any, username: string, password: string, callback: any) => {
  if (username === 'test' && password === 'test') {
    callback(null, true)
  } else {
    const error = new Error() as Error & { returnCode: number }
    error.returnCode = 1

    callback(error, false)
  }
}

const Aedes = Aedes({
  authenticate: authCallback
})

Since we cannot re-export packet typings from mqtt-packet like it's done on MQTT.js, usage of those typings require explicit import by the user as well.

Those might or might not be deal-breakers.

[mcollina]

I’m good with not re-exporting the packet types.

[mcollina]

This can be any Duplex.

[saboya]

Fixed.

[mcollina]

Can you use && instead of ;?

[saboya]

Sure, I was just sticking to what was already in place :)

[mcollina]

LGTM