Yieldables

Starting with ember-concurrency v2.1.0, Yieldables are a new addition to the public API to provide a way to instrument TaskInstances. The API provides a safe mechanism to implement custom waiters, hooks, introspection, and other operations in a task definition, from application code.

There are many great uses for yieldables, and indeed many of them are already built-in to ember-concurrency today. Yieldables like animationFrame, timeout, and rawTimeout provide safe, cancelation-aware ways to delay execution of a task. Cancelable Promise helpers like all, and hashSettled are too a form of yieldable.

While there are many built-in forms that provide cancelation-aware wrappers around common browser APIs, you can also define domain-specific yieldables for use within your application or complementary addons. This allows you to implement behavior that would be inappropriate for inclusion in ember-concurrency itself.

Defining a new yieldable

Let's suppose you want to create a Task-aware, cancelable wrapper for the requestIdleCallback browser API, in order to write tasks that pause until the browser has time to execute some lower-priority tasks.

Now that we have a yieldable defined, we can import and use it in any tasks that we wish.

More about Yieldables

The behavior and implementation of yieldables are defined further in the Yieldables RFC. Additionally, the API for Yieldable is documented here.