SettlementSignal

Kind: Class

Source: packages/core/injector/settlement-signal.ts

Part of: Core

SettlementSignal is used to signal the resolution of a provider/instance. Calling complete or error will resolve the promise returned by asPromise. Can be used to detect circular dependencies.

SettlementSignal coordinates the lifecycle of a provider or instance while it is being resolved by the injector. Calling complete() or error() settles the promise returned by asPromise(), while reference tracking through insertRef() and isCycle() helps identify circular dependencies.

Methods

Diagram

mermaid
graph LR
  Injector[Injector resolving provider] --> Signal[SettlementSignal]
  Signal --> Promise[asPromise()]
  Signal -->|complete()| Resolved[Provider resolved]
  Signal -->|error()| Failed[Provider resolution failed]
  Signal -->|insertRef()| References[Resolution references]
  References -->|isCycle()| Cycle[Circular dependency detected]

Usage

ts
import { SettlementSignal } from "./settlement-signal";

async function resolveProvider() {
  const signal = new SettlementSignal();

  const resolution = signal.asPromise();

  try {
    // Create and initialize the provider instance.
    const instance = { connected: true };

    signal.complete();

    await resolution;
    return instance;
  } catch (error) {
    signal.error();
    throw error;
  }
}

AI Coding Instructions

• Create a SettlementSignal for each in-progress provider or instance resolution that must be observed asynchronously.
• Call complete() only after the provider has been fully constructed and initialized.
• Call error() when resolution fails so consumers awaiting asPromise() are unblocked.
• Use insertRef() while traversing dependency references, then check isCycle() before continuing resolution.
• Avoid awaiting asPromise() from a dependency path that has already been identified as circular.