this.disposable is undefined

Summary

I have run into a case where the typeof check below returns undefined:

SliceSink.prototype.dispose = function () {
  console.log("calling dispose", typeof this.disposable)
  console.log("this", this)
  return this.disposable.dispose()
}

TypeError: Cannot read property 'dispose' of undefined
    at SliceSink.dispose (build/main.js:20834:25)
    at SliceSink.event (build/main.js:20826:10)
    at tryEvent (build/main.js:2483:10)
    at SubscriberSink.next (build/main.js:22463:92)
    at SubscriptionObserver.next (build/main.js:23958:14)
    at observerNext (build/main.js:6253:16)
    at addListener (build/main.js:18989:17)
    at attachListenerToElement (build/main.js:19101:13)
    at utils.forEach (build/main.js:5604:22)
    at Object.listenTo (build/main.js:19025:9)

Expected result

this.disposable should never be undefined or a better error for the user.

Actual Result

this.disposable is undefined

Versions

• most.js: ^1.2.2

Steps to reproduce

See code below

Code to reproduce

const FRP = require("most")
const Observable = require("zen-observable")



const makeProblemStream = () =>
  new Observable((observer) => {
    observer.next(1) // <-- Triggers error
    const intervalId = setInterval(
      () => { observer.next(1) },
      1000
    )
    return () => clearInterval(intervalId)
  })

FRP
.from(makeProblemStream())
.take(1)
.drain()
.catch(console.error)

[jasonkuhrt]

Could you try it in your larger use case to see if it helps there as well?

Hey @briancavalier I just tried out your branch in forto and it works!

On a side note, just wanted say thanks for your fantastic OSS contributions. More over, you conduct yourself with an amazing humility and humanity… its always a pleasure to interact with you!

[briancavalier]

Great, thanks @jasonkuhrt. I’ll start to dig into this.