promise-preserve

Preserve the result in a promise chain.

Install

npm install --save `promise-preserve`

Usage

var preserve = require('promise-preserve');

var promise = new Promise(function(resolve, reject) {
  resolve('Hello world!');
});

promise.then(preserve(function(result) {
  console.log(result); // prints 'Hello world!';
  return 'foobar';
}).then(function(result) {
  // prints 'Hello world!'; as promise-preserve preserved the value of the
  // promise chain
  console.log(result);
  return 'foobar';
}).then(function(result) {
  // prints 'foobar' as the previous function did not preserve the result
  console.log(result);
});

API

preserve(fn) preserve a function

Wraps the function so that when it is called, it does not modify the result in a promise chain.

preserve(obj, name) preserve a method

Wraps the method so that when it is called, it will be called with the right context and it will not change the result in a promise chain.