can-define-stream

Add useful stream conversion methods to a supplied can-define/map/map or can-define/list/list constructor using a stream interface such as can-stream-kefir.

`canDefineStream(streamInterface)`

The can-define-stream module exports a function that takes a streamInterface and returns a function that takes a DefineMap.prototype or DefineList.prototype and uses the supplied stream interface to create streamed property definitions.

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

var Person = DefineMap.extend({
    first: "string",
    last: "string",
    fullName: {
        get: function() {
            return this.first + " " + this.last;
        }
    },
    fullNameChangeCount: {
        stream: function() {
            return this.toStream(".fullName").scan(function(last) {
                return last + 1;
            }, 0);
        }
    }
});

canDefineStream(canStream)(Person);

var me = new Person({name: "Justin", last: "Meyer"});

me.on("fullNameChangeCount", function(ev, newVal) {
    console.log(newVal);
});
me.fullNameChangeCount //-> 0
me.first = "Obaid"; //-> console.logs 1
me.last = "Ahmed"; //-> console.logs 2

Parameters

streamInterface {streamInterface()}:
A streamInterface function. See can-stream-kefir for implementation.

Returns

{function}:

A function that takes a DefineMap.prototype or DefineList.prototype.

Use

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

toStream("eventName")           //-> stream
toStream(".propName")           //-> stream
toStream(".propName eventName") //-> stream

For example:

Update map property based on stream value

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

var Person = DefineMap.extend({
    name: "string",
    lastValidName: {
        stream: function() {
            return this.toStream(".name").filter(function(name) { // using propName
                return name.indexOf(" ") >= 0;
            });
        }
    }
});

canDefineStream(canStream)(Person);

var me = new Person({name: "James"});

me.on("lastValidName", function(lastValid) {});

me.name = "JamesAtherton"; //lastValidName -> undefined
me.name = "James Atherton"; //lastValidName -> James Atherton

Stream on DefineList

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

var PeopleList = DefineList.extend({});

canDefineStream(canStream)(PeopleList);

var people = new PeopleList([
    { first: "Justin", last: "Meyer" },
    { first: "Paula", last: "Strozak" }
]);

var stream = people.toStream('length'); // using eventName

stream.onValue(function(val) {
    val //-> 2, 3
});

people.push({
    first: 'Obaid',
    last: 'Ahmed'
}); //-> stream.onValue -> 3