implexus-common v1.0.0

implexus-common

A bunch of common stream factories that one could use to get up and running with implexus.

npm install --save implexus-common

Example:

var Implexus = require("implexus");
var implexus = new Implexus();

// Add all the stream types at once
var streams = require("implexus-common");
implexus.define(modules);

var map = require("implexus-common/map");
implexus.define("map", map);

API

value

This outputs a single value

properties

• value : Either a JSON value, or a string.

example

This should output "foo" and {bar:"baz"} to the console or stdout

digraph {
	C[type=stdout];
	A[type=value value=foo] -> C;
	B[type=value value="{\"bar\":\"baz\"}"] -> C;
}

stdout

Outputs input to either the console, or stdout.

properties

• prefix : A string to prefix all output with

example

This should output Log:foo to stdout.

digraph {
	A[type=value value=foo] -> B[type=stdout prefix="Log:"];
}

array

This takes in an array of items that it will emit one by one

properties

• list : A string that contains items split by commas. The items can be any valid JSON.

example

This should output the items to stdout one by one.

digraph {
	A[type=array, list="1,2,3,4,5"] -> B[type=stdout];
}

delay

Takes in arbitrary inputs, and outputs it after a given time.

properties

• time : The time in milliseconds to delay before outputting. Defaults to 1000 milliseconds.

example

This should delay for 2 seconds and output the stdout.

digraph {
	A[type=delay time=2000] -> B[type="stdout"];
}

concat

Concatenates inputted items and emits every time a new item is added

properties

• initial : The initial state of the array. A string that contains items split by commas. The items can be any valid JSON.

example

This should build up an array and emit [1] [1,2] [1,2,3]

digraph {
	A[type=array, list="1,2,3"] -> B[type=concat] -> C[type=stdout];
}

map

Processes incoming data with JavaScript and outputs the result.

properties

• code : Some JavaScript to execute on every piece of data. Within the code, you can reference data as the incoming data.

example

This should go through a list of numbers and multiply them by two.

digraph {
	A[type=array list="0,1,2"];
	B[type=map code="data * 2"];
	C[type=stdout];

	A -> B -> C;
}

websocket

This creates a websocket to a given URL.

properties

• url : The URL to connect the websocket to.

example

This should open a websocket and output everything from it to stdout.

digraph {
	A[type=websocket url="ws://example.com"] -> B[type=stdout];
}

toJSON

Converts incoming data to a JSON string. Each JSON item is separated by a newline.

example

This should convert an object into a JSON string.

digraph {
	A[type=value value="{}"];
	B[type=toJSON];
	C[type=websocket url="ws://example.com"];

	A -> B -> C;
}

fromJSON

Converts incoming JSON strings into objects.

example

This will convert data from a websockt into objects, and then output them to stdout.

digraph {
	A[type=websocket url="ws://example.com"];
	B[type=parseJSON];
	C[type=stdout];

	A -> B -> C;
}

debounce

Limits the number of times it emits data.

properties

• interval : How frequently it lets data through. Once the interval is over, it'l output the most recent bit of data. The default is 1000 milliseconds.

example

This will output every other item in the array. Should output 1, 4.

digraph {
	A[type=array list="1,2,3,4"];
	B[type=delay time=500];
	C[type=debounce time=1000];
	D[type=stdout];

	A -> B -> C -> D;
}

merge

Merges inputted objects together.

properties

• state : The initial state to merge with. A JSON string. An empty object by default.
• depth : The depth at which to merge with. Merges fully by default.

examples

This should merge the two values together, and output whatever one emits first, and then the two merged together.

digraph {
	A[type=value value="{\"foo\":1337}"];
	B[type=value value="{\"bar\":21337}"];
	C[type=stdout];

	A -> C;
	B -> C;
}

getProp

Takes in a stream of objects, outputs a certain property from within them.

properties

• prop : The property to fetch out. This is required in order to create the stream.

example

digraph {
	A[type=getProp prop="foo.bar"];
}

makeProp

Takes in a stream of values and outputs objects with the value under a certain property

properties

• prop : What property to wrap inputted values under. This is required in order to create the stream.

example

This will take in the value foo, and output the object {bar:{baz:"foo"}}.

digraph {
	A[type=value value="foo"] -> B[type=makeProp prop="bar.baz"] -> C[type=stdout];
}