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Continuables (or Thunk)

General

A continuable represents an asynchronous operation that returns a value or an error. It also referred to as a thunk.

Terminology

  1. "value" is any legal JavaScript value.
  2. "error" is a value that represents an error. It must not be falsey.
  3. "continuation" is a function which takes two arguments, an error and a value
  4. "continuable" is a function which takes a continuation as an argument
  5. "resolution" are the results that will be passed to a given continuation of a continuable. The resolution is either an error or a value, not both.
  6. "async function" is a function which does an asynchronous operation. An async function will return a continuable.

Requirements

The Continuable datatype.

A Continuable must be a function. It accepts a single argument:

continuable(function continuation(err, value) { })
  1. continuation is a required argument and it must be a function
    1. The continuable must produce a single resolution for this continuation. This resolution may be synchronous or asynchronous
      1. If the resolution is a value then the continuation must be called with null as the "error" and the value.
      2. If the resolution is an error then the continuation must be called with the error as the "error"

Notes

That's it. Dead simple.

continuable(function continuation(err, value) {
    // the continuable has produced a resolution

    if (err) {
        // the continuable resoluted to an error.
    } else {
        // the continuable resoluted to a value.
    }
})
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