can-stream

module

Convert observable values into streams. Kefir is used internally to provide the stream functionality.

`Object`

The can-stream module exports methods useful for converting observable values like can-computes or can-define/map/map properties into streams.

var canStream = require("can-stream");
var DefineMap = require("can-define/map/map");

var me = new DefineMap({name: "Justin"});

var nameStream = canStream.toStream(me,".name");


nameStream.onValue(function(name){
    // name -> "Obaid";
});

me.name = "Obaid";

Usage

The toStream method has shorthands for all of the other methods:

var canStream = require("can-stream");

canStream.toStream(compute)                    //-> stream
canStream.toStream(map, "eventName")           //-> stream
canStream.toStream(map, ".propName")           //-> stream
canStream.toStream(map, ".propName eventName") //-> stream

For example:

Converting a compute to a stream

var canCompute = require("can-compute");
var canStream = require("can-stream");

var compute = canCompute(0);
var stream = canStream.toStream(compute);

stream.onValue(function(newVal){
    console.log(newVal);
});

compute(1);
//-> console.logs 1

Converting an event to a stream

var DefineList = require('can-define/list/list');
var canStream = require('can-stream');

var hobbies = new DefineList(["js","kayaking"]);

var changeCount = canStream.toStream(obs, "length").scan(function(prev){
    return prev + 1;
}, 0);
changeCount.onValue(function(event) {
    console.log(event);
});

hobbies.push("bball")
//-> console.logs {type: "add", args: [2,["bball"]]}
hobbies.shift()
//-> console.logs {type: "remove", args: [0,["js"]]}

Converting a property value to a stream

var canStream = require('can-stream');
var DefineMap = require("can-define/map/map");

var person = new DefineMap({
    first: "Justin",
    last: "Meyer"
});

var first = canStream.toStream(person, '.first'),
    last = canStream.toStream(person, '.last');

var fullName = Kefir.combine(first, last, function(first, last){
    return first + last;
});

fullName.onValue(function(newVal){
    console.log(newVal);
});

map.first = "Payal"
//-> console.logs "Payal Meyer"

Converting an event on a nested object into a stream

var canStream = require('can-stream');
var DefineMap = require("can-define/map/map");
var DefineList = require("can-define/list/list");

var me = new DefineMap({
    todos: ["mow lawn"]
});

var addStream = canStream.toStream(me, ".todos add");

addStream.onValue(function(event){
    console.log(event);
});

map.todos.push("do dishes");
//-> console.logs {type: "add", args: [1,["do dishes"]]}