promise-branch

Allows isolated branching of promise flows.

This lib helps to address some of the issues raised by: Broken Promises

Install

npm install --save promise-branch

API

branch(target, onResolved, onRejected)

promise-branch will ensure a rejected promise which occured before branching the flow is ignored and proxied on down the main promise chain. This means the error handler of promise-branch will only handle a rejected promise caused by the target promise/ promise factory.

• target (Promise|Function): a promise or function that returns a promise.
• onResolved (Function): a function that returns a promise. This is called if target resolves.
• onRejected (Function): a function that returns a promise. This is called if target rejects.

Example

const branch = requires('promise-branch');
 
initialAsyncWork()
.then(() => 
  branch(
    secondaryAsyncWork(), // this can be a promise, or a function that returns a promise
    successHandler,
    errorHandler // this only handles a rejection from secondaryAsyncWork
  )
)
.then(continuedAsyncWork)
.catch(errorAsyncWork);