プロミスのパイプラインを動的に拡張するための仕組み

promise_injection.js

var addtioalTask(pipeline){
    pipeline.push(function(p){ return p.then(function(v){console.log(v);return v}) });
}

var pipeline = [];
addtionalTask(pipeline);
pipeline.push(function(p){ return p.then(function(v){return v}) });
pipeline.reduce(function(p, f){ return f(p) }, promiseAync());

promise_task.js

var util = require('util');
var event = require('events');
var Promise = require('bluebird');

var PromiseTask = module.exports = function(){
    event.EventEmitter.call(this);
    this.pipeline = [];
}
util.inherits(PromiseTask, event.EventEmitter);

PromiseTask.prototype.addThen = function(f){
    this.pipeline.push(function(p){ return p.then(f) });
}
PromiseTask.prototype.addWatch = function(name){
    if(!name) name = '';
    var self = this;
    this.addThen(function(v){self.emit('watch', v, name); return v});
}
PromiseTask.prototype.add = function(f, name){
    this.addThen(f);
    this.addWatch(name);
}

PromiseTask.prototype.run = function(promise){
    if(!(promise instanceof Array)){
        promise = [promise];
    }
    var self = this;
    this.pipeline.push(function(p){ return p.then(function(result){ self.emit('complete', result) }) });
    this.pipeline.push(function(p){ return p.catch(function(err){ self.emit('error', err) }) });
    this.pipeline.reduce(function(p, f){ return f(p) }, Promise.all(promise));
}

妄想してみたけどあまり必要ないのかもしれない
ボトムアップ的なアプローチの利点が消える

promiseタスクの方は流れてるデータを動的にウォッチできるけどどうだろうなぁ