promise-observer-example.js

var observer = require('promise-observer')
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 emit;
    var onTransaction = observer.create(function(e) { emit = e; })
    return {
        subscribe: onTransaction,
        start: function(id) {
          var tx = mkTransaction(id);
          return emit(tx.query).then(tx.close)
        }
    }
}

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)
    });


    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();

No problem with Yaku. Which version are you using?

PO [ [ 1, 2, 3, 'close 1' ],
  [ 1, 2, 3, 'close 2' ],
  [ 1, 2, 3, 'close 3' ] ]
Yaku [ [ 1, 2, 3, 'close 1' ],
  [ 1, 2, 3, 'close 2' ],
  [ 1, 2, 3, 'close 3' ] ]

@ysmood npm ls says

├── [email protected]
├── [email protected]
└── [email protected]

Works with the original example, but not with the updated one where the starts are delayed