function action

Create an Operation that can be either resolved (or rejected) with a synchronous callback. This is the Effection equivalent of new Promise().

The action body is a function that enters the effect, and returns a function that will be called to exit the action..

For example:

let five = yield* action((resolve, reject) => {
  let timeout = setTimeout(() => {
    if (Math.random() > 5) {
      resolve(5)
    } else {
      reject(new Error("bad luck!"));
    }
  }, 1000);
  return () => clearTimeout(timeout);
});

Type Parameters

T

• type of the action's result.

Parameters

enter: (resolve: Resolve<T>, reject: Reject) => () => void

• enter and exit the action

Return Type

Operation<T>

an operation producing the resolved value, or throwing the rejected error