requirebin sketch

index.js

var Kefir = require( "kefir" )

var plusButton = document.getElementById( "plus-btn" )
var minusButton = document.getElementById( "minus-btn" )

var plusClicks = Kefir.fromEvent( plusButton , "click" )
var minusClicks = Kefir.fromEvent( minusButton , "click" )

var counterChanges = Kefir.merge(
  [ plusClicks.mapTo(1) , minusClicks.mapTo(-1) ]
)

counterChanges
  .scan(sum, 0)
  .onValue( updateResults )

function sum (a, b) {
  return a + b
}

function updateResults (n)
{ 
  document.getElementById( "result" ).innerHTML = n 
}

minified.js

require=function e(t,n,r){function s(o,u){if(!n[o]){if(!t[o]){var a=typeof require=="function"&&require;if(!u&&a)return a(o,!0);if(i)return i(o,!0);var f=new Error("Cannot find module '"+o+"'");throw f.code="MODULE_NOT_FOUND",f}var l=n[o]={exports:{}};t[o][0].call(l.exports,function(e){var n=t[o][1][e];return s(n?n:e)},l,l.exports,e,t,n,r)}return n[o].exports}var i=typeof require=="function"&&require;for(var o=0;o<r.length;o++)s(r[o]);return s}({kefir:[function(require,module,exports){(function(global){"use strict";var Kefir={};function and(){for(var i=0;i<arguments.length;i++){if(!arguments[i]){return arguments[i]}}return arguments[i-1]}function or(){for(var i=0;i<arguments.length;i++){if(arguments[i]){return arguments[i]}}return arguments[i-1]}function not(x){return!x}function concat(a,b){var result,length,i,j;if(a.length===0){return b}if(b.length===0){return a}j=0;result=new Array(a.length+b.length);length=a.length;for(i=0;i<length;i++,j++){result[j]=a[i]}length=b.length;for(i=0;i<length;i++,j++){result[j]=b[i]}return result}function circleShift(arr,distance){var length=arr.length,result=new Array(length),i;for(i=0;i<length;i++){result[(i+distance)%length]=arr[i]}return result}function find(arr,value){var length=arr.length,i;for(i=0;i<length;i++){if(arr[i]===value){return i}}return-1}function findByPred(arr,pred){var length=arr.length,i;for(i=0;i<length;i++){if(pred(arr[i])){return i}}return-1}function cloneArray(input){var length=input.length,result=new Array(length),i;for(i=0;i<length;i++){result[i]=input[i]}return result}function remove(input,index){var length=input.length,result,i,j;if(index>=0&&index<length){if(length===1){return[]}else{result=new Array(length-1);for(i=0,j=0;i<length;i++){if(i!==index){result[j]=input[i];j++}}return result}}else{return input}}function removeByPred(input,pred){return remove(input,findByPred(input,pred))}function map(input,fn){var length=input.length,result=new Array(length),i;for(i=0;i<length;i++){result[i]=fn(input[i])}return result}function forEach(arr,fn){var length=arr.length,i;for(i=0;i<length;i++){fn(arr[i])}}function fillArray(arr,value){var length=arr.length,i;for(i=0;i<length;i++){arr[i]=value}}function contains(arr,value){return find(arr,value)!==-1}function rest(arr,start,onEmpty){if(arr.length>start){return Array.prototype.slice.call(arr,start)}return onEmpty}function slide(cur,next,max){var length=Math.min(max,cur.length+1),offset=cur.length-length+1,result=new Array(length),i;for(i=offset;i<length;i++){result[i-offset]=cur[i]}result[length-1]=next;return result}function isEqualArrays(a,b){var length,i;if(a==null&&b==null){return true}if(a==null||b==null){return false}if(a.length!==b.length){return false}for(i=0,length=a.length;i<length;i++){if(a[i]!==b[i]){return false}}return true}function spread(fn,length){switch(length){case 0:return function(a){return fn()};case 1:return function(a){return fn(a[0])};case 2:return function(a){return fn(a[0],a[1])};case 3:return function(a){return fn(a[0],a[1],a[2])};case 4:return function(a){return fn(a[0],a[1],a[2],a[3])};default:return function(a){return fn.apply(null,a)}}}function apply(fn,c,a){var aLength=a?a.length:0;if(c==null){switch(aLength){case 0:return fn();case 1:return fn(a[0]);case 2:return fn(a[0],a[1]);case 3:return fn(a[0],a[1],a[2]);case 4:return fn(a[0],a[1],a[2],a[3]);default:return fn.apply(null,a)}}else{switch(aLength){case 0:return fn.call(c);default:return fn.apply(c,a)}}}function get(map,key,notFound){if(map&&key in map){return map[key]}else{return notFound}}function own(obj,prop){return Object.prototype.hasOwnProperty.call(obj,prop)}function createObj(proto){var F=function(){};F.prototype=proto;return new F}function extend(target){var length=arguments.length,i,prop;for(i=1;i<length;i++){for(prop in arguments[i]){target[prop]=arguments[i][prop]}}return target}function inherit(Child,Parent){var length=arguments.length,i;Child.prototype=createObj(Parent.prototype);Child.prototype.constructor=Child;for(i=2;i<length;i++){extend(Child.prototype,arguments[i])}return Child}var NOTHING=["<nothing>"];var END="end";var VALUE="value";var ERROR="error";var ANY="any";function noop(){}function id(x){return x}function id2(_,x){return x}function strictEqual(a,b){return a===b}function defaultDiff(a,b){return[a,b]}var now=Date.now?function(){return Date.now()}:function(){return(new Date).getTime()};var log=typeof console!==undefined&&isFn(console.log)?function(m){console.log(m)}:noop;function isFn(fn){return typeof fn==="function"}function isUndefined(x){return typeof x==="undefined"}function isArrayLike(xs){return isArray(xs)||isArguments(xs)}var isArray=Array.isArray||function(xs){return Object.prototype.toString.call(xs)==="[object Array]"};var isArguments=function(xs){return Object.prototype.toString.call(xs)==="[object Arguments]"};if(!isArguments(arguments)){isArguments=function(obj){return!!(obj&&own(obj,"callee"))}}function withInterval(name,mixin){function AnonymousStream(wait,args){Stream.call(this);this._wait=wait;this._intervalId=null;var $=this;this._$onTick=function(){$._onTick()};this._init(args)}inherit(AnonymousStream,Stream,{_name:name,_init:function(args){},_free:function(){},_onTick:function(){},_onActivation:function(){this._intervalId=setInterval(this._$onTick,this._wait)},_onDeactivation:function(){if(this._intervalId!==null){clearInterval(this._intervalId);this._intervalId=null}},_clear:function(){Stream.prototype._clear.call(this);this._$onTick=null;this._free()}},mixin);Kefir[name]=function(wait){return new AnonymousStream(wait,rest(arguments,1,[]))}}function withOneSource(name,mixin,options){options=extend({streamMethod:function(StreamClass,PropertyClass){return function(){return new StreamClass(this,arguments)}},propertyMethod:function(StreamClass,PropertyClass){return function(){return new PropertyClass(this,arguments)}}},options||{});mixin=extend({_init:function(args){},_free:function(){},_handleValue:function(x,isCurrent){this._send(VALUE,x,isCurrent)},_handleError:function(x,isCurrent){this._send(ERROR,x,isCurrent)},_handleEnd:function(__,isCurrent){this._send(END,null,isCurrent)},_handleAny:function(event){switch(event.type){case VALUE:this._handleValue(event.value,event.current);break;case ERROR:this._handleError(event.value,event.current);break;case END:this._handleEnd(event.value,event.current);break}},_onActivation:function(){this._source.onAny(this._$handleAny)},_onDeactivation:function(){this._source.offAny(this._$handleAny)}},mixin||{});function buildClass(BaseClass){function AnonymousObservable(source,args){BaseClass.call(this);this._source=source;this._name=source._name+"."+name;this._init(args);var $=this;this._$handleAny=function(event){$._handleAny(event)}}inherit(AnonymousObservable,BaseClass,{_clear:function(){BaseClass.prototype._clear.call(this);this._source=null;this._$handleAny=null;this._free()}},mixin);return AnonymousObservable}var AnonymousStream=buildClass(Stream);var AnonymousProperty=buildClass(Property);if(options.streamMethod){Stream.prototype[name]=options.streamMethod(AnonymousStream,AnonymousProperty)}if(options.propertyMethod){Property.prototype[name]=options.propertyMethod(AnonymousStream,AnonymousProperty)}}function withTwoSources(name,mixin){mixin=extend({_init:function(args){},_free:function(){},_handlePrimaryValue:function(x,isCurrent){this._send(VALUE,x,isCurrent)},_handlePrimaryError:function(x,isCurrent){this._send(ERROR,x,isCurrent)},_handlePrimaryEnd:function(__,isCurrent){this._send(END,null,isCurrent)},_handleSecondaryValue:function(x,isCurrent){this._lastSecondary=x},_handleSecondaryError:function(x,isCurrent){this._send(ERROR,x,isCurrent)},_handleSecondaryEnd:function(__,isCurrent){},_handlePrimaryAny:function(event){switch(event.type){case VALUE:this._handlePrimaryValue(event.value,event.current);break;case ERROR:this._handlePrimaryError(event.value,event.current);break;case END:this._handlePrimaryEnd(event.value,event.current);break}},_handleSecondaryAny:function(event){switch(event.type){case VALUE:this._handleSecondaryValue(event.value,event.current);break;case ERROR:this._handleSecondaryError(event.value,event.current);break;case END:this._handleSecondaryEnd(event.value,event.current);this._removeSecondary();break}},_removeSecondary:function(){if(this._secondary!==null){this._secondary.offAny(this._$handleSecondaryAny);this._$handleSecondaryAny=null;this._secondary=null}},_onActivation:function(){if(this._secondary!==null){this._secondary.onAny(this._$handleSecondaryAny)}if(this._alive){this._primary.onAny(this._$handlePrimaryAny)}},_onDeactivation:function(){if(this._secondary!==null){this._secondary.offAny(this._$handleSecondaryAny)}this._primary.offAny(this._$handlePrimaryAny)}},mixin||{});function buildClass(BaseClass){function AnonymousObservable(primary,secondary,args){BaseClass.call(this);this._primary=primary;this._secondary=secondary;this._name=primary._name+"."+name;this._lastSecondary=NOTHING;var $=this;this._$handleSecondaryAny=function(event){$._handleSecondaryAny(event)};this._$handlePrimaryAny=function(event){$._handlePrimaryAny(event)};this._init(args)}inherit(AnonymousObservable,BaseClass,{_clear:function(){BaseClass.prototype._clear.call(this);this._primary=null;this._secondary=null;this._lastSecondary=null;this._$handleSecondaryAny=null;this._$handlePrimaryAny=null;this._free()}},mixin);return AnonymousObservable}var AnonymousStream=buildClass(Stream);var AnonymousProperty=buildClass(Property);Stream.prototype[name]=function(secondary){return new AnonymousStream(this,secondary,rest(arguments,1,[]))};Property.prototype[name]=function(secondary){return new AnonymousProperty(this,secondary,rest(arguments,1,[]))}}function callSubscriber(sType,sFn,event){if(sType===ANY){sFn(event)}else if(sType===event.type){if(sType===VALUE||sType===ERROR){sFn(event.value)}else{sFn()}}}function Dispatcher(){this._items=[]}extend(Dispatcher.prototype,{add:function(type,fn,_key){this._items=concat(this._items,[{type:type,fn:fn,key:_key||null}]);return this._items.length},remove:function(type,fn,_key){var pred=isArray(_key)?function(fnData){return fnData.type===type&&isEqualArrays(fnData.key,_key)}:function(fnData){return fnData.type===type&&fnData.fn===fn};this._items=removeByPred(this._items,pred);return this._items.length},dispatch:function(event){var items=this._items;for(var i=0;i<items.length;i++){callSubscriber(items[i].type,items[i].fn,event)}}});function Event(type,value,current){return{type:type,value:value,current:!!current}}var CURRENT_END=Event(END,undefined,true);function Observable(){this._dispatcher=new Dispatcher;this._active=false;this._alive=true}Kefir.Observable=Observable;extend(Observable.prototype,{_name:"observable",_onActivation:function(){},_onDeactivation:function(){},_setActive:function(active){if(this._active!==active){this._active=active;if(active){this._onActivation()}else{this._onDeactivation()}}},_clear:function(){this._setActive(false);this._alive=false;this._dispatcher=null},_send:function(type,x,isCurrent){if(this._alive){this._dispatcher.dispatch(Event(type,x,isCurrent));if(type===END){this._clear()}}},_on:function(type,fn,_key){if(this._alive){this._dispatcher.add(type,fn,_key);this._setActive(true)}else{callSubscriber(type,fn,CURRENT_END)}return this},_off:function(type,fn,_key){if(this._alive){var count=this._dispatcher.remove(type,fn,_key);if(count===0){this._setActive(false)}}return this},onValue:function(fn,_key){return this._on(VALUE,fn,_key)},onError:function(fn,_key){return this._on(ERROR,fn,_key)},onEnd:function(fn,_key){return this._on(END,fn,_key)},onAny:function(fn,_key){return this._on(ANY,fn,_key)},offValue:function(fn,_key){return this._off(VALUE,fn,_key)},offError:function(fn,_key){return this._off(ERROR,fn,_key)},offEnd:function(fn,_key){return this._off(END,fn,_key)},offAny:function(fn,_key){return this._off(ANY,fn,_key)}});Observable.prototype.toString=function(){return"["+this._name+"]"};function Stream(){Observable.call(this)}Kefir.Stream=Stream;inherit(Stream,Observable,{_name:"stream"});function Property(){Observable.call(this);this._current=NOTHING;this._currentError=NOTHING}Kefir.Property=Property;inherit(Property,Observable,{_name:"property",_send:function(type,x,isCurrent){if(this._alive){if(!isCurrent){this._dispatcher.dispatch(Event(type,x))}if(type===VALUE){this._current=x}if(type===ERROR){this._currentError=x}if(type===END){this._clear()}}},_on:function(type,fn,_key){if(this._alive){this._dispatcher.add(type,fn,_key);this._setActive(true)}if(this._current!==NOTHING){callSubscriber(type,fn,Event(VALUE,this._current,true))}if(this._currentError!==NOTHING){callSubscriber(type,fn,Event(ERROR,this._currentError,true))}if(!this._alive){callSubscriber(type,fn,CURRENT_END)}return this}});Observable.prototype.log=function(name){name=name||this.toString();this.onAny(function(event){var typeStr="<"+event.type+(event.current?":current":"")+">";if(event.type===VALUE||event.type===ERROR){console.log(name,typeStr,event.value)}else{console.log(name,typeStr)}},["__logKey__",this,name]);return this};Observable.prototype.offLog=function(name){name=name||this.toString();this.offAny(null,["__logKey__",this,name]);return this};withInterval("withInterval",{_init:function(args){this._fn=args[0];var $=this;this._emitter={emit:function(x){$._send(VALUE,x)},error:function(x){$._send(ERROR,x)},end:function(){$._send(END)},emitEvent:function(e){$._send(e.type,e.value)}}},_free:function(){this._fn=null;this._emitter=null},_onTick:function(){this._fn(this._emitter)}});withInterval("fromPoll",{_init:function(args){this._fn=args[0]},_free:function(){this._fn=null},_onTick:function(){this._send(VALUE,this._fn())}});withInterval("interval",{_init:function(args){this._x=args[0]},_free:function(){this._x=null},_onTick:function(){this._send(VALUE,this._x)}});withInterval("sequentially",{_init:function(args){this._xs=cloneArray(args[0]);if(this._xs.length===0){this._send(END)}},_free:function(){this._xs=null},_onTick:function(){switch(this._xs.length){case 1:this._send(VALUE,this._xs[0]);this._send(END);break;default:this._send(VALUE,this._xs.shift())}}});withInterval("repeatedly",{_init:function(args){this._xs=cloneArray(args[0]);this._i=-1},_onTick:function(){if(this._xs.length>0){this._i=(this._i+1)%this._xs.length;this._send(VALUE,this._xs[this._i])}}});withInterval("later",{_init:function(args){this._x=args[0]},_free:function(){this._x=null},_onTick:function(){this._send(VALUE,this._x);this._send(END)}});function _AbstractPool(options){Stream.call(this);this._queueLim=get(options,"queueLim",0);this._concurLim=get(options,"concurLim",-1);this._drop=get(options,"drop","new");if(this._concurLim===0){throw new Error("options.concurLim can't be 0")}var $=this;this._$handleSubAny=function(event){$._handleSubAny(event)};this._queue=[];this._curSources=[];this._activating=false}inherit(_AbstractPool,Stream,{_name:"abstractPool",_add:function(obj,toObs){toObs=toObs||id;if(this._concurLim===-1||this._curSources.length<this._concurLim){this._addToCur(toObs(obj))}else{if(this._queueLim===-1||this._queue.length<this._queueLim){this._addToQueue(toObs(obj))}else if(this._drop==="old"){this._removeOldest();this._add(toObs(obj))}}},_addAll:function(obss){var $=this;forEach(obss,function(obs){$._add(obs)})},_remove:function(obs){if(this._removeCur(obs)===-1){this._removeQueue(obs)}},_addToQueue:function(obs){this._queue=concat(this._queue,[obs])},_addToCur:function(obs){this._curSources=concat(this._curSources,[obs]);if(this._active){this._subscribe(obs)}},_subscribe:function(obs){var $=this;obs.onAny(this._$handleSubAny);obs.onEnd(function(){$._removeCur(obs)},[this,obs])},_unsubscribe:function(obs){obs.offAny(this._$handleSubAny);obs.offEnd(null,[this,obs])},_handleSubAny:function(event){if(event.type===VALUE||event.type===ERROR){this._send(event.type,event.value,event.current&&this._activating)}},_removeQueue:function(obs){var index=find(this._queue,obs);this._queue=remove(this._queue,index);return index},_removeCur:function(obs){if(this._active){this._unsubscribe(obs)}var index=find(this._curSources,obs);this._curSources=remove(this._curSources,index);if(index!==-1){if(this._queue.length!==0){this._pullQueue()}else if(this._curSources.length===0){this._onEmpty()}}return index},_removeOldest:function(){this._removeCur(this._curSources[0])},_pullQueue:function(){if(this._queue.length!==0){this._queue=cloneArray(this._queue);this._addToCur(this._queue.shift())}},_onActivation:function(){var sources=this._curSources,i;this._activating=true;for(i=0;i<sources.length;i++){if(this._active){this._subscribe(sources[i])}}this._activating=false},_onDeactivation:function(){var sources=this._curSources,i;for(i=0;i<sources.length;i++){this._unsubscribe(sources[i])}},_isEmpty:function(){return this._curSources.length===0},_onEmpty:function(){},_clear:function(){Stream.prototype._clear.call(this);this._queue=null;this._curSources=null;this._$handleSubAny=null}});var MergeLike={_onEmpty:function(){if(this._initialised){this._send(END,null,this._activating)}}};function Merge(sources){_AbstractPool.call(this);if(sources.length===0){this._send(END)}else{this._addAll(sources)}this._initialised=true}inherit(Merge,_AbstractPool,extend({_name:"merge"},MergeLike));Kefir.merge=function(obss){return new Merge(obss)};Observable.prototype.merge=function(other){return Kefir.merge([this,other])};function Concat(sources){_AbstractPool.call(this,{concurLim:1,queueLim:-1});if(sources.length===0){this._send(END)}else{this._addAll(sources)}this._initialised=true}inherit(Concat,_AbstractPool,extend({_name:"concat"},MergeLike));Kefir.concat=function(obss){return new Concat(obss)};Observable.prototype.concat=function(other){return Kefir.concat([this,other])};function Pool(){_AbstractPool.call(this)}Kefir.Pool=Pool;inherit(Pool,_AbstractPool,{_name:"pool",plug:function(obs){this._add(obs);return this},unplug:function(obs){this._remove(obs);return this}});Kefir.pool=function(){return new Pool};function Bus(){_AbstractPool.call(this)}Kefir.Bus=Bus;inherit(Bus,_AbstractPool,{_name:"bus",plug:function(obs){this._add(obs);return this},unplug:function(obs){this._remove(obs);return this},emit:function(x){this._send(VALUE,x);return this},error:function(x){this._send(ERROR,x);return this},end:function(){this._send(END);return this},emitEvent:function(event){this._send(event.type,event.value)}});Kefir.bus=function(){return new Bus};function FlatMap(source,fn,options){_AbstractPool.call(this,options);this._source=source;this._fn=fn||id;this._mainEnded=false;this._lastCurrent=null;var $=this;this._$handleMainSource=function(event){$._handleMainSource(event)}}inherit(FlatMap,_AbstractPool,{_onActivation:function(){_AbstractPool.prototype._onActivation.call(this);if(this._active){this._activating=true;this._source.onAny(this._$handleMainSource);this._activating=false}},_onDeactivation:function(){_AbstractPool.prototype._onDeactivation.call(this);this._source.offAny(this._$handleMainSource)},_handleMainSource:function(event){if(event.type===VALUE){if(!event.current||this._lastCurrent!==event.value){this._add(event.value,this._fn)}this._lastCurrent=event.value}if(event.type===ERROR){this._send(ERROR,event.value,event.current)}if(event.type===END){if(this._isEmpty()){this._send(END,null,event.current)}else{this._mainEnded=true}}},_onEmpty:function(){if(this._mainEnded){this._send(END)}},_clear:function(){_AbstractPool.prototype._clear.call(this);this._source=null;this._lastCurrent=null;this._$handleMainSource=null}});Observable.prototype.flatMap=function(fn){return new FlatMap(this,fn).setName(this,"flatMap")};Observable.prototype.flatMapLatest=function(fn){return new FlatMap(this,fn,{concurLim:1,drop:"old"}).setName(this,"flatMapLatest")};Observable.prototype.flatMapFirst=function(fn){return new FlatMap(this,fn,{concurLim:1}).setName(this,"flatMapFirst")};Observable.prototype.flatMapConcat=function(fn){return new FlatMap(this,fn,{queueLim:-1,concurLim:1}).setName(this,"flatMapConcat")};Observable.prototype.flatMapConcurLimit=function(fn,limit){var result;if(limit===0){result=Kefir.never()}else{if(limit<0){limit=-1}result=new FlatMap(this,fn,{queueLim:-1,concurLim:limit})}return result.setName(this,"flatMapConcurLimit")};function Zip(sources,combinator){Stream.call(this);if(sources.length===0){this._send(END)}else{this._buffers=map(sources,function(source){return isArray(source)?cloneArray(source):[]});this._sources=map(sources,function(source){return isArray(source)?Kefir.never():source});this._combinator=combinator?spread(combinator,this._sources.length):id;this._aliveCount=0}}inherit(Zip,Stream,{_name:"zip",_onActivation:function(){var i,length=this._sources.length;this._drainArrays();this._aliveCount=length;for(i=0;i<length;i++){if(this._active){this._sources[i].onAny(this._bindHandleAny(i),[this,i])}}},_onDeactivation:function(){for(var i=0;i<this._sources.length;i++){this._sources[i].offAny(null,[this,i])}},_emit:function(isCurrent){var values=new Array(this._buffers.length);for(var i=0;i<this._buffers.length;i++){values[i]=this._buffers[i].shift()}this._send(VALUE,this._combinator(values),isCurrent)},_isFull:function(){for(var i=0;i<this._buffers.length;i++){if(this._buffers[i].length===0){return false}}return true},_emitIfFull:function(isCurrent){if(this._isFull()){this._emit(isCurrent)}},_drainArrays:function(){while(this._isFull()){this._emit(true)}},_bindHandleAny:function(i){var $=this;return function(event){$._handleAny(i,event)}},_handleAny:function(i,event){if(event.type===VALUE){this._buffers[i].push(event.value);this._emitIfFull(event.current)}if(event.type===ERROR){this._send(ERROR,event.value,event.current)}if(event.type===END){this._aliveCount--;if(this._aliveCount===0){this._send(END,null,event.current)}}},_clear:function(){Stream.prototype._clear.call(this);this._sources=null;this._buffers=null;this._combinator=null}});Kefir.zip=function(sources,combinator){return new Zip(sources,combinator)};Observable.prototype.zip=function(other,combinator){return new Zip([this,other],combinator)};function Combine(active,passive,combinator){Stream.call(this);if(active.length===0){this._send(END)}else{this._activeCount=active.length;this._sources=concat(active,passive);this._combinator=combinator?spread(combinator,this._sources.length):id;this._aliveCount=0;this._currents=new Array(this._sources.length);fillArray(this._currents,NOTHING);this._activating=false;this._emitAfterActivation=false;this._endAfterActivation=false}}inherit(Combine,Stream,{_name:"combine",_onActivation:function(){var length=this._sources.length,i;this._aliveCount=this._activeCount;this._activating=true;for(i=0;i<length;i++){this._sources[i].onAny(this._bindHandleAny(i),[this,i])}this._activating=false;if(this._emitAfterActivation){this._emitAfterActivation=false;this._emitIfFull(true)}if(this._endAfterActivation){this._send(END,null,true)}},_onDeactivation:function(){var length=this._sources.length,i;for(i=0;i<length;i++){this._sources[i].offAny(null,[this,i])}},_emitIfFull:function(isCurrent){if(!contains(this._currents,NOTHING)){var combined=cloneArray(this._currents);combined=this._combinator(combined);this._send(VALUE,combined,isCurrent)}},_bindHandleAny:function(i){var $=this;return function(event){$._handleAny(i,event)}},_handleAny:function(i,event){if(event.type===VALUE){this._currents[i]=event.value;if(i<this._activeCount){if(this._activating){this._emitAfterActivation=true}else{this._emitIfFull(event.current)}}}if(event.type===ERROR){this._send(ERROR,event.value,event.current)}if(event.type===END){if(i<this._activeCount){this._aliveCount--;if(this._aliveCount===0){if(this._activating){this._endAfterActivation=true}else{this._send(END,null,event.current)}}}}},_clear:function(){Stream.prototype._clear.call(this);this._sources=null;this._currents=null;this._combinator=null}});Kefir.combine=function(active,passive,combinator){if(isFn(passive)){combinator=passive;passive=null}return new Combine(active,passive||[],combinator)};Observable.prototype.combine=function(other,combinator){return Kefir.combine([this,other],combinator)};Kefir.DISABLE_SAMPLEDBY_WARNING=false;Kefir.sampledBy=function(passive,active,combinator){if(!Kefir.DISABLE_SAMPLEDBY_WARNING){log("Kefir.sampledBy() is deprecated, and to be removed in v3.0.0.\n"+"Use Kefir.combine(active, passive, combinator) instead, "+"but note than active/passive order is different.\n"+"To disable this warning set Kefir.DISABLE_SAMPLEDBY_WARNING to true.")}var _combinator=combinator;if(passive.length>0){var passiveLength=passive.length;_combinator=function(){var args=circleShift(arguments,passiveLength);return combinator?apply(combinator,null,args):args}}return new Combine(active,passive,_combinator).setName("sampledBy")};Observable.prototype.sampledBy=function(other,combinator){var _combinator;if(combinator){_combinator=function(active,passive){return combinator(passive,active)}}return new Combine([other],[this],_combinator||id2).setName(this,"sampledBy")};function produceStream(StreamClass,PropertyClass){return function(){return new StreamClass(this,arguments)}}function produceProperty(StreamClass,PropertyClass){return function(){return new PropertyClass(this,arguments)}}withOneSource("toProperty",{_init:function(args){if(args.length>0){this._send(VALUE,args[0])}}},{propertyMethod:produceProperty,streamMethod:produceProperty});withOneSource("changes",{_handleValue:function(x,isCurrent){if(!isCurrent){this._send(VALUE,x)}},_handleError:function(x,isCurrent){if(!isCurrent){this._send(ERROR,x)}}},{streamMethod:function(){return function(){return this}},propertyMethod:produceStream});withOneSource("withHandler",{_init:function(args){this._handler=args[0];this._forcedCurrent=false;var $=this;this._emitter={emit:function(x){$._send(VALUE,x,$._forcedCurrent)},error:function(x){$._send(ERROR,x,$._forcedCurrent)},end:function(){$._send(END,null,$._forcedCurrent)},emitEvent:function(e){$._send(e.type,e.value,$._forcedCurrent)}}},_free:function(){this._handler=null;this._emitter=null},_handleAny:function(event){this._forcedCurrent=event.current;this._handler(this._emitter,event);this._forcedCurrent=false}});withOneSource("flatten",{_init:function(args){this._fn=args[0]?args[0]:id},_free:function(){this._fn=null},_handleValue:function(x,isCurrent){var xs=this._fn(x);for(var i=0;i<xs.length;i++){this._send(VALUE,xs[i],isCurrent)}}});function xformForObs(obs){return{step:function(res,input){obs._send(VALUE,input,obs._forcedCurrent);return null},result:function(res){obs._send(END,null,obs._forcedCurrent);return null}}}withOneSource("transduce",{_init:function(args){this._xform=args[0](xformForObs(this))},_free:function(){this._xform=null},_handleValue:function(x,isCurrent){this._forcedCurrent=isCurrent;if(this._xform.step(null,x)!==null){this._xform.result(null)}this._forcedCurrent=false},_handleEnd:function(__,isCurrent){this._forcedCurrent=isCurrent;this._xform.result(null);this._forcedCurrent=false}});var withFnArgMixin={_init:function(args){this._fn=args[0]||id},_free:function(){this._fn=null}};withOneSource("map",extend({_handleValue:function(x,isCurrent){this._send(VALUE,this._fn(x),isCurrent)}},withFnArgMixin));withOneSource("mapErrors",extend({_handleError:function(x,isCurrent){this._send(ERROR,this._fn(x),isCurrent)}},withFnArgMixin));function defaultErrorsToValuesHandler(x){return{convert:true,value:x}}withOneSource("errorsToValues",extend({_init:function(args){this._fn=args[0]||defaultErrorsToValuesHandler},_free:function(){this._fn=null},_handleError:function(x,isCurrent){var result=this._fn(x);var type=result.convert?VALUE:ERROR;var newX=result.convert?result.value:x;this._send(type,newX,isCurrent)}}));function defaultValuesToErrorsHandler(x){return{convert:true,error:x}}withOneSource("valuesToErrors",extend({_init:function(args){this._fn=args[0]||defaultValuesToErrorsHandler},_free:function(){this._fn=null},_handleValue:function(x,isCurrent){var result=this._fn(x);var type=result.convert?ERROR:VALUE;var newX=result.convert?result.error:x;this._send(type,newX,isCurrent)}}));withOneSource("filter",extend({_handleValue:function(x,isCurrent){if(this._fn(x)){this._send(VALUE,x,isCurrent)}}},withFnArgMixin));withOneSource("filterErrors",extend({_handleError:function(x,isCurrent){if(this._fn(x)){this._send(ERROR,x,isCurrent)}}},withFnArgMixin));withOneSource("takeWhile",extend({_handleValue:function(x,isCurrent){if(this._fn(x)){this._send(VALUE,x,isCurrent)}else{this._send(END,null,isCurrent)}}},withFnArgMixin));withOneSource("take",{_init:function(args){this._n=args[0];if(this._n<=0){this._send(END)}},_handleValue:function(x,isCurrent){this._n--;this._send(VALUE,x,isCurrent);if(this._n===0){this._send(END,null,isCurrent)}}});withOneSource("skip",{_init:function(args){this._n=Math.max(0,args[0])},_handleValue:function(x,isCurrent){if(this._n===0){this._send(VALUE,x,isCurrent)}else{this._n--}}});withOneSource("skipDuplicates",{_init:function(args){this._fn=args[0]||strictEqual;this._prev=NOTHING},_free:function(){this._fn=null;this._prev=null},_handleValue:function(x,isCurrent){if(this._prev===NOTHING||!this._fn(this._prev,x)){this._prev=x;this._send(VALUE,x,isCurrent)}}});withOneSource("skipWhile",{_init:function(args){this._fn=args[0]||id;this._skip=true},_free:function(){this._fn=null},_handleValue:function(x,isCurrent){if(!this._skip){this._send(VALUE,x,isCurrent);return}if(!this._fn(x)){this._skip=false;this._fn=null;this._send(VALUE,x,isCurrent)}}});withOneSource("diff",{_init:function(args){this._fn=args[0]||defaultDiff;this._prev=args.length>1?args[1]:NOTHING},_free:function(){this._prev=null;this._fn=null},_handleValue:function(x,isCurrent){if(this._prev!==NOTHING){this._send(VALUE,this._fn(this._prev,x),isCurrent)}this._prev=x}});withOneSource("scan",{_init:function(args){this._fn=args[0];if(args.length>1){this._send(VALUE,args[1],true)}},_free:function(){this._fn=null},_handleValue:function(x,isCurrent){if(this._current!==NOTHING){x=this._fn(this._current,x)}this._send(VALUE,x,isCurrent)}},{streamMethod:produceProperty});withOneSource("reduce",{_init:function(args){this._fn=args[0];this._result=args.length>1?args[1]:NOTHING},_free:function(){this._fn=null;this._result=null},_handleValue:function(x){this._result=this._result===NOTHING?x:this._fn(this._result,x)},_handleEnd:function(__,isCurrent){if(this._result!==NOTHING){this._send(VALUE,this._result,isCurrent)}this._send(END,null,isCurrent)}});withOneSource("mapEnd",{_init:function(args){this._fn=args[0]},_free:function(){this._fn=null},_handleEnd:function(__,isCurrent){this._send(VALUE,this._fn(),isCurrent);this._send(END,null,isCurrent)}});withOneSource("skipValues",{_handleValue:function(){}});withOneSource("skipErrors",{_handleError:function(){}});withOneSource("skipEnd",{_handleEnd:function(){}});withOneSource("endOnError",extend({_handleError:function(x,isCurrent){this._send(ERROR,x,isCurrent);this._send(END,null,isCurrent)}}));withOneSource("slidingWindow",{_init:function(args){this._max=args[0];this._min=args[1]||0;this._buff=[]},_free:function(){this._buff=null},_handleValue:function(x,isCurrent){this._buff=slide(this._buff,x,this._max);if(this._buff.length>=this._min){this._send(VALUE,this._buff,isCurrent)}}});withOneSource("bufferWhile",{_init:function(args){this._fn=args[0]||id;this._flushOnEnd=get(args[1],"flushOnEnd",true);this._buff=[]},_free:function(){this._buff=null},_flush:function(isCurrent){if(this._buff!==null&&this._buff.length!==0){this._send(VALUE,this._buff,isCurrent);this._buff=[]}},_handleValue:function(x,isCurrent){this._buff.push(x);if(!this._fn(x)){this._flush(isCurrent)}},_handleEnd:function(x,isCurrent){if(this._flushOnEnd){this._flush(isCurrent)}this._send(END,null,isCurrent)}});withOneSource("debounce",{_init:function(args){this._wait=Math.max(0,args[0]);this._immediate=get(args[1],"immediate",false);this._lastAttempt=0;this._timeoutId=null;this._laterValue=null;this._endLater=false;var $=this;this._$later=function(){$._later();

}},_free:function(){this._laterValue=null;this._$later=null},_handleValue:function(x,isCurrent){if(isCurrent){this._send(VALUE,x,isCurrent)}else{this._lastAttempt=now();if(this._immediate&&!this._timeoutId){this._send(VALUE,x)}if(!this._timeoutId){this._timeoutId=setTimeout(this._$later,this._wait)}if(!this._immediate){this._laterValue=x}}},_handleEnd:function(__,isCurrent){if(isCurrent){this._send(END,null,isCurrent)}else{if(this._timeoutId&&!this._immediate){this._endLater=true}else{this._send(END)}}},_later:function(){var last=now()-this._lastAttempt;if(last<this._wait&&last>=0){this._timeoutId=setTimeout(this._$later,this._wait-last)}else{this._timeoutId=null;if(!this._immediate){this._send(VALUE,this._laterValue);this._laterValue=null}if(this._endLater){this._send(END)}}}});withOneSource("throttle",{_init:function(args){this._wait=Math.max(0,args[0]);this._leading=get(args[1],"leading",true);this._trailing=get(args[1],"trailing",true);this._trailingValue=null;this._timeoutId=null;this._endLater=false;this._lastCallTime=0;var $=this;this._$trailingCall=function(){$._trailingCall()}},_free:function(){this._trailingValue=null;this._$trailingCall=null},_handleValue:function(x,isCurrent){if(isCurrent){this._send(VALUE,x,isCurrent)}else{var curTime=now();if(this._lastCallTime===0&&!this._leading){this._lastCallTime=curTime}var remaining=this._wait-(curTime-this._lastCallTime);if(remaining<=0){this._cancelTraling();this._lastCallTime=curTime;this._send(VALUE,x)}else if(this._trailing){this._cancelTraling();this._trailingValue=x;this._timeoutId=setTimeout(this._$trailingCall,remaining)}}},_handleEnd:function(__,isCurrent){if(isCurrent){this._send(END,null,isCurrent)}else{if(this._timeoutId){this._endLater=true}else{this._send(END)}}},_cancelTraling:function(){if(this._timeoutId!==null){clearTimeout(this._timeoutId);this._timeoutId=null}},_trailingCall:function(){this._send(VALUE,this._trailingValue);this._timeoutId=null;this._trailingValue=null;this._lastCallTime=!this._leading?0:now();if(this._endLater){this._send(END)}}});withOneSource("delay",{_init:function(args){this._wait=Math.max(0,args[0]);this._buff=[];var $=this;this._$shiftBuff=function(){$._send(VALUE,$._buff.shift())}},_free:function(){this._buff=null;this._$shiftBuff=null},_handleValue:function(x,isCurrent){if(isCurrent){this._send(VALUE,x,isCurrent)}else{this._buff.push(x);setTimeout(this._$shiftBuff,this._wait)}},_handleEnd:function(__,isCurrent){if(isCurrent){this._send(END,null,isCurrent)}else{var $=this;setTimeout(function(){$._send(END)},this._wait)}}});function FromBinder(fn){Stream.call(this);this._fn=fn;this._unsubscribe=null}inherit(FromBinder,Stream,{_name:"fromBinder",_onActivation:function(){var $=this,isCurrent=true,emitter={emit:function(x){$._send(VALUE,x,isCurrent)},error:function(x){$._send(ERROR,x,isCurrent)},end:function(){$._send(END,null,isCurrent)},emitEvent:function(e){$._send(e.type,e.value,isCurrent)}};this._unsubscribe=this._fn(emitter)||null;if(!this._active&&this._unsubscribe!==null){this._unsubscribe();this._unsubscribe=null}isCurrent=false},_onDeactivation:function(){if(this._unsubscribe!==null){this._unsubscribe();this._unsubscribe=null}},_clear:function(){Stream.prototype._clear.call(this);this._fn=null}});Kefir.fromBinder=function(fn){return new FromBinder(fn)};function Emitter(){Stream.call(this)}inherit(Emitter,Stream,{_name:"emitter",emit:function(x){this._send(VALUE,x);return this},error:function(x){this._send(ERROR,x);return this},end:function(){this._send(END);return this},emitEvent:function(event){this._send(event.type,event.value)}});Kefir.emitter=function(){return new Emitter};Kefir.Emitter=Emitter;var neverObj=new Stream;neverObj._send(END);neverObj._name="never";Kefir.never=function(){return neverObj};function Constant(x){Property.call(this);this._send(VALUE,x);this._send(END)}inherit(Constant,Property,{_name:"constant"});Kefir.constant=function(x){return new Constant(x)};function ConstantError(x){Property.call(this);this._send(ERROR,x);this._send(END)}inherit(ConstantError,Property,{_name:"constantError"});Kefir.constantError=function(x){return new ConstantError(x)};function Repeat(generator){Stream.call(this);this._generator=generator;this._source=null;this._inLoop=false;this._activating=false;this._iteration=0;var $=this;this._$handleAny=function(event){$._handleAny(event)}}inherit(Repeat,Stream,{_name:"repeat",_handleAny:function(event){if(event.type===END){this._source=null;this._startLoop()}else{this._send(event.type,event.value,this._activating)}},_startLoop:function(){if(!this._inLoop){this._inLoop=true;while(this._source===null&&this._alive&&this._active){this._source=this._generator(this._iteration++);if(this._source){this._source.onAny(this._$handleAny)}else{this._send(END)}}this._inLoop=false}},_onActivation:function(){this._activating=true;if(this._source){this._source.onAny(this._$handleAny)}else{this._startLoop()}this._activating=false},_onDeactivation:function(){if(this._source){this._source.offAny(this._$handleAny)}},_clear:function(){Stream.prototype._clear.call(this);this._generator=null;this._source=null;this._$handleAny=null}});Kefir.repeat=function(generator){return new Repeat(generator)};Observable.prototype.setName=function(sourceObs,selfName){this._name=selfName?sourceObs._name+"."+selfName:sourceObs;return this};Observable.prototype.mapTo=function(value){return this.map(function(){return value}).setName(this,"mapTo")};Observable.prototype.pluck=function(propertyName){return this.map(function(x){return x[propertyName]}).setName(this,"pluck")};Observable.prototype.invoke=function(methodName){var args=rest(arguments,1);return this.map(args?function(x){return apply(x[methodName],x,args)}:function(x){return x[methodName]()}).setName(this,"invoke")};Observable.prototype.timestamp=function(){return this.map(function(x){return{value:x,time:now()}}).setName(this,"timestamp")};Observable.prototype.tap=function(fn){return this.map(function(x){fn(x);return x}).setName(this,"tap")};Kefir.and=function(observables){return Kefir.combine(observables,and).setName("and")};Observable.prototype.and=function(other){return this.combine(other,and).setName("and")};Kefir.or=function(observables){return Kefir.combine(observables,or).setName("or")};Observable.prototype.or=function(other){return this.combine(other,or).setName("or")};Observable.prototype.not=function(){return this.map(not).setName(this,"not")};Observable.prototype.awaiting=function(other){return Kefir.merge([this.mapTo(true),other.mapTo(false)]).skipDuplicates().toProperty(false).setName(this,"awaiting")};Kefir.fromCallback=function(callbackConsumer){var called=false;return Kefir.fromBinder(function(emitter){if(!called){callbackConsumer(function(x){emitter.emit(x);emitter.end()});called=true}}).setName("fromCallback")};Kefir.fromNodeCallback=function(callbackConsumer){var called=false;return Kefir.fromBinder(function(emitter){if(!called){callbackConsumer(function(error,x){if(error){emitter.error(error)}else{emitter.emit(x)}emitter.end()});called=true}}).setName("fromNodeCallback")};Kefir.fromPromise=function(promise){var called=false;return Kefir.fromBinder(function(emitter){if(!called){var onValue=function(x){emitter.emit(x);emitter.end()};var onError=function(x){emitter.error(x);emitter.end()};var _promise=promise.then(onValue,onError);if(_promise&&isFn(_promise.done)){_promise.done()}called=true}}).toProperty().setName("fromPromise")};Kefir.fromSubUnsub=function(sub,unsub,transformer){return Kefir.fromBinder(function(emitter){var handler=transformer?function(){emitter.emit(apply(transformer,this,arguments))}:emitter.emit;sub(handler);return function(){unsub(handler)}})};var subUnsubPairs=[["addEventListener","removeEventListener"],["addListener","removeListener"],["on","off"]];Kefir.fromEvent=function(target,eventName,transformer){var pair,sub,unsub;for(var i=0;i<subUnsubPairs.length;i++){pair=subUnsubPairs[i];if(isFn(target[pair[0]])&&isFn(target[pair[1]])){sub=pair[0];unsub=pair[1];break}}if(sub===undefined){throw new Error("target don't support any of "+"addEventListener/removeEventListener, addListener/removeListener, on/off method pair")}return Kefir.fromSubUnsub(function(handler){target[sub](eventName,handler)},function(handler){target[unsub](eventName,handler)},transformer).setName("fromEvent")};var withTwoSourcesAndBufferMixin={_init:function(args){this._buff=[];this._flushOnEnd=get(args[0],"flushOnEnd",true)},_free:function(){this._buff=null},_flush:function(isCurrent){if(this._buff!==null&&this._buff.length!==0){this._send(VALUE,this._buff,isCurrent);this._buff=[]}},_handlePrimaryEnd:function(__,isCurrent){if(this._flushOnEnd){this._flush(isCurrent)}this._send(END,null,isCurrent)}};withTwoSources("bufferBy",extend({_onActivation:function(){this._primary.onAny(this._$handlePrimaryAny);if(this._alive&&this._secondary!==null){this._secondary.onAny(this._$handleSecondaryAny)}},_handlePrimaryValue:function(x,isCurrent){this._buff.push(x)},_handleSecondaryValue:function(x,isCurrent){this._flush(isCurrent)},_handleSecondaryEnd:function(x,isCurrent){if(!this._flushOnEnd){this._send(END,null,isCurrent)}}},withTwoSourcesAndBufferMixin));withTwoSources("bufferWhileBy",extend({_handlePrimaryValue:function(x,isCurrent){this._buff.push(x);if(this._lastSecondary!==NOTHING&&!this._lastSecondary){this._flush(isCurrent)}},_handleSecondaryEnd:function(x,isCurrent){if(!this._flushOnEnd&&(this._lastSecondary===NOTHING||this._lastSecondary)){this._send(END,null,isCurrent)}}},withTwoSourcesAndBufferMixin));withTwoSources("filterBy",{_handlePrimaryValue:function(x,isCurrent){if(this._lastSecondary!==NOTHING&&this._lastSecondary){this._send(VALUE,x,isCurrent)}},_handleSecondaryEnd:function(__,isCurrent){if(this._lastSecondary===NOTHING||!this._lastSecondary){this._send(END,null,isCurrent)}}});withTwoSources("skipUntilBy",{_handlePrimaryValue:function(x,isCurrent){if(this._lastSecondary!==NOTHING){this._send(VALUE,x,isCurrent)}},_handleSecondaryEnd:function(__,isCurrent){if(this._lastSecondary===NOTHING){this._send(END,null,isCurrent)}}});withTwoSources("takeUntilBy",{_handleSecondaryValue:function(x,isCurrent){this._send(END,null,isCurrent)}});withTwoSources("takeWhileBy",{_handlePrimaryValue:function(x,isCurrent){if(this._lastSecondary!==NOTHING){this._send(VALUE,x,isCurrent)}},_handleSecondaryValue:function(x,isCurrent){this._lastSecondary=x;if(!this._lastSecondary){this._send(END,null,isCurrent)}},_handleSecondaryEnd:function(__,isCurrent){if(this._lastSecondary===NOTHING){this._send(END,null,isCurrent)}}});withTwoSources("skipWhileBy",{_init:function(){this._hasFalseyFromSecondary=false},_handlePrimaryValue:function(x,isCurrent){if(this._hasFalseyFromSecondary){this._send(VALUE,x,isCurrent)}},_handleSecondaryValue:function(x,isCurrent){this._hasFalseyFromSecondary=this._hasFalseyFromSecondary||!x},_handleSecondaryEnd:function(__,isCurrent){if(!this._hasFalseyFromSecondary){this._send(END,null,isCurrent)}}});if(typeof define==="function"&&define.amd){define([],function(){return Kefir});global.Kefir=Kefir}else if(typeof module==="object"&&typeof exports==="object"){module.exports=Kefir;Kefir.Kefir=Kefir}else{global.Kefir=Kefir}})(this)},{}]},{},[]);var Kefir=require("kefir");var plusButton=document.getElementById("plus-btn");var minusButton=document.getElementById("minus-btn");var plusClicks=Kefir.fromEvent(plusButton,"click");var minusClicks=Kefir.fromEvent(minusButton,"click");var counterChanges=Kefir.merge([plusClicks.mapTo(1),minusClicks.mapTo(-1)]);counterChanges.scan(sum,0).onValue(updateResults);function sum(a,b){return a*b}function updateResults(n){document.getElementById("result").innerHTML=n}

package.json

{
  "name": "requirebin-sketch",
  "version": "1.0.0",
  "dependencies": {
    "kefir": "1.2.0"
  }
}

page-body.html

<button id="plus-btn">+</button>
<span id="result"></span>
<button id="minus-btn">-</button>

requirebin.md

made with requirebin