pull-unwind

Unwind/flatten a complex stream to a simpler one.

Similar behaviour to MongoDB's $unwind in the aggregation framework.

Usage

unwind(?unwindBy)

unwindBy can be an integer or a property name. If you're unwinding a stream, you can leave this arg blank.

If it's an integer X, the event would be cloned X times.

If it's a property name, it will check whether the value of a property is an integer or an array. If it's an integer it will work the same way as specifying an integer.

In case it's an array, the array will be unwinded and it's contents would be extended to the base object, one-by-one.

In case it's a stream, it'll unwind it.

Examples

unwindBy is blank (unwinding streams)

var pull = require("pull-stream");
var unwind = require("pull-unwind");
 
var streamOfStreams = pull.values([
    pull.values([1,2,3,4,5]),
    pull.values([6,7,8])
]);
 
pull(
  streamOfStreams,
  unwind(),
  pull.log()
)

unwindBy is an Integer

var pull = require("pull-stream");
var unwind = require("pull-unwind");
 
var events = [
  {
    name: "SomeEvent",
    value: 1
  }
]
 
pull(
  pull.values(events),
  unwind(3),
  pull.drain(console.log)
)

Result:

{ name: 'SomeEvent', value: 1 }
{ name: 'SomeEvent', value: 1 }
{ name: 'SomeEvent', value: 1 }

unwindBy is a property name with integer value

var pull = require("pull-stream");
var unwind = require("pull-unwind");
 
var events = [
  {
    name: "SomeEvent",
    value: 1,
    clones: 2
  }
]
 
pull(
  pull.values(events),
  unwind('clones'),
  pull.drain(console.log)
)

Result:

{ name: 'SomeEvent', value: 1 }
{ name: 'SomeEvent', value: 1 }

unwindBy is a property name with array as value

var pull = require("pull-stream");
var unwind = require("pull-unwind");
 
var events = [
  {
    name: "SomeEvent",
    collection: [
      {value: 1},
      {value: 2}
    ]
  }
]
 
pull(
  pull.values(events),
  unwind('collection'),
  pull.drain(console.log)
)

Result:

{ name: 'SomeEvent', value: 1 }
{ name: 'SomeEvent', value: 2 }

install

With npm do:

npm install pull-unwind

license

MIT