Inspect signal outcomes

A signal terminates exactly once by succeeding with a value, failing, or closing without a value. These states are mutually exclusive.

`outcome()`

outcome(signal) converts every terminal state into an ordinary tagged value:

import { outcome } from "automate.ax"

const resultOutcome = outcome(result)
// Signal<
//   | { status: "succeeded"; value: Result }
//   | { status: "failed"; failure: SignalFailure }
//   | { status: "closed" }
// >

The returned signal always succeeds after the source terminates.

Source outcome	`outcome`	`succeeded`	`failed`	`closed`	`onSuccess`	`onFailure`	`onClose`
Succeeded	Tagged value	`true`	`false`	`false`	Source value	Closes	Closes
Failed	Tagged failure	`false`	`true`	`false`	Closes	Failure value	Closes
Closed	Tagged closure	`false`	`false`	`true`	Closes	Closes	`null`

`succeeded()`

succeeded(signal) emits whether the source succeeded after it terminates.

`failed()`

failed(signal) emits whether the source failed after it terminates.

`closed()`

closed(signal) emits whether the source closed without a value after it terminates. Failure is not closure.

`onSuccess()`

onSuccess(signal) emits the successful source value and closes for failure or closure. Unlike consuming the source directly, it suppresses failure. It preserves a keyed or global source partition.

`onFailure()`

onFailure(signal) emits { name, message } when the source fails and closes for success or closure.

import { onFailure, scope } from "automate.ax"

const failure = onFailure(result)

scope(failure, () => {
  sendEmail({ subject: "Action failed", text: failure.message })
})

`onClose()`

onClose(signal) emits null when the source closes and closes for success or failure. Use routing and scopes to declare recovery work under a selective outcome. Use fallback when closure should advance to another value but failure should remain selected.

Get started

Guides

Concepts

Reference

Inspect signal outcomes

`outcome()`

`succeeded()`

`failed()`

`closed()`

`onSuccess()`

`onFailure()`

`onClose()`

​outcome()

​succeeded()

​failed()

​closed()

​onSuccess()

​onFailure()

​onClose()

`outcome()`

`succeeded()`

`failed()`

`closed()`

`onSuccess()`

`onFailure()`

`onClose()`