# Ocafe

Once a callback attached to the first emitted event

[![Build status for Node.js 0.x and newer](https://github.com/sovpro/ocafe/workflows/Node.js%200.x%20and%20newer%20/badge.svg?branch=master)](https://github.com/sovpro/ocafe/commits/master)

## Usage

```js
var cancel = ocafe (
    event_emitter
  , 'thisEvent'
  , thisEventCallback
  , { event: 'thatEvent' ,
      callback: thatEventCallback }
)
```

## Parameters

#### Event Emitter

The first parameter must be an object that inherits EventEmitter or implements the EventEmitter interface.

#### Event names and callbacks

Event names and callbacks may be passed as ordered arguments and/or objects having an `event` and `callback` property.

## Cancellation

```js
var cancel = ocafe (
  event_emitter
  // , [name], [callback]
  // , [name], [callback]
)
// cancelled is true if called before
// any of the events above emitted
var cancelled = cancel ()
```

`ocafe` returns a `cancel` function that, if called before one of the events is emitted, will prevent the callbacks passed as arguments from being run.