no-async-constructor

Disallows async work inside constructors.

Rule details Problem

Constructors return before async work finishes. This rule reports patterns that leave an instance half-initialized or drop promise errors on the floor.

It reports:

• await inside a constructor
• promise chains like .then(), .catch(), and .finally()
• async IIFEs called from the constructor
• bare calls to async methods on this, such as this.load()
• promises from async methods stored in a local variable and never used

It does not report this.loadPromise = this.load();, because the promise stays on the instance and can be consumed by callers.

No options

This rule has no configuration. If async setup is required, move it to a factory or an explicit init step.

Examples

Incorrect

class Database {
  constructor() {
    this.connect().then(() => logReady());
  }

  async connect() {}
}

Correct

class Database {
  private constructor() {}

  static async create() {
    const database = new Database();
    await database.connect();
    return database;
  }

  async connect() {}
}

Common refactors

• use static async create() when construction depends on async setup
• expose an init() method and make callers await it before use
• if you must start work in the constructor, store the promise on this so the lifecycle is visible

Related rules

require-module-level-instantiation Keeps singleton-style setup at module scope