promise-observer-example.js

var Observable = require('yaku/lib/Observable')
var Promise = require('bluebird');
var assert = require('assert');

function mkTransaction(tId) {
    var queries = []
    return {
        query: function query(q) { queries.push(q); return query },
        close: function() { queries.push('close ' + tId); return queries; }
    }
}

function makeEnvironment() {
    var trans = new Observable();
    return {
        subscribe: trans.subscribe.bind(trans),
        start: function(id) {
            var tx = mkTransaction(id);

            var out = Observable.all(trans.subscribers.slice(0, 3)).subscribe(tx.close);
            trans.emit(tx.query);

            return new Promise(out.subscribe.bind(out));
        }
    }
}

function test() {
    var env = makeEnvironment();

    var q1 = env.subscribe(function(q) {
        return Promise.resolve(1).delay(1).then(q)
    });
    var q2 = env.subscribe(function(q) {
        return Promise.resolve(2).delay(9).then(q)
    });
    var q3 = env.subscribe(function(q){
        return Promise.resolve(3).delay(20).then(q)
    });
    var q4 = env.subscribe(function(q){
        return new Promise(function () {});
    });


    env.start(1).then(function(queries) {
        console.log(queries);
        assert.deepEqual(queries, [1,2,3,'close 1']);
    })

    env.start(2).then(function(queries) {
        console.log(queries);
        assert.deepEqual(queries, [1,2,3,'close 2']);
    })
}

test();