Classes

Keeps track of all promises in a promise chain with pending or currently running tasks, and cancels them all when cancel is called.

Tracks the cancel items for a CancellablePromise. These items are removed from the associated CancelContext when the promise resolves.

Cancellable finalizer returned from catch. Use finally to specify a code block that executes when the promise chain resolves.

A CancellableGuarantee is a functional abstraction around an asynchronous operation that can be cancelled but cannot error.

When a cancellable guarantee is cancelled any associated tasks are cancelled but the chain completes successfully. In this situation the guarantee would successfully resolve with whatever value the task returns after being cancelled – perhaps an error, nil, an empty string, or a zero length array. Alternatively, the cancelValue optional parameter explicitly specifies a value to use when the guarantee is cancelled.

A CancellablePromise is a functional abstraction around a failable and cancellable asynchronous operation.

At runtime the promise can become a member of a chain of promises, where the cancelContext is used to track and cancel (if desired) all promises in this chain.