callbackify
backwards compatibilify your callback functions while migrating apis to promises
usage
var callbackify = var getUserById = // later in your code, we can use a callback // but for newer code, we can consume it as a promise
callbackify
will also preserve the this
context of your functions:
getUserById// the underlying promise-returning function is called with the supplied context argument
Normally, callbackify will only work with fixed-parameter-length functions, and will use the declared parameter length to determine if the extra callback argument is present. If you need to use callbackify with variadic functions, or functions that don't declare their full argument list, you can use:
// options argument is optionalvar getUserById = callbackify // we can do either of these
Note that this will not work if the last argument your function can take is a function, as that last argument will always be detected as a callback function.
api
callbackify : (fn: (...args) => Promise<T> ) => (...args, Callback<T>) => Promise<T>
Takes a Promise-returning function fn
and returns a new function which can return a Promise or take a callback as the last parameter. If a callback is supplied, the function returns void. If no callback is supplied, the promise is returned.
installation
$ npm install callbackify
running the tests
From package root:
$ npm install
$ npm test
contributors
- jden jason@denizac.org
- tootallnate nathan@tootallnate.net
license
MIT. (c) MMXIII jden jason@denizac.org. See LICENSE.md