through2-map-promise

A small promise-based wrapper for through2. Allows you to easily map over data in a stream while using promises for flow control.

Quickstart

npm install --save through2-map-promise

1var map = require("through2-map-promise");
2var xtend = require("xtend");
3
4// in an HTTP request handler
5db.users.find({}).pipe(map(function(user){
6    var locationId = user.location;
7    return db.locations.findOne({_id: locationId}).then(function(location){
8        return xtend(user, {
9            location: location
10        });
11    });
12})).pipe(response);

API

through2-map-promise([options,] [fn])

Creates a transform stream which calls your transforming function, fn. You can throw within your function to automatically reject the promise and error-out the stream. options is the optional object that gets passed into through2.

through2-map-promise.obj([options,] [fn])

Same as the former, but the stream is created in objectMode

through2-map-promise.ctor([options,] [fn])

Creates a constructor for your transform stream in case you want to be more efficient