Powerful and fast macro-based data binding engine inspired by Flex Bindings with easy-to-use syntax.

bind, binding, bindings, cross, haxe
haxelib install bindx2 2.7.0


bindx2 - crossplatform library for data binding in Haxe.

Build Status



  • automatically generates signals to notify about properties/methods changes of a class
  • automatically generates setters or modifies existing setters
  • neat API for subscribing to properties and methods changes
  • extended API for custom expressions binding
  • API for fast properties binding
  • support @:bindable attribute in interfaces



// UserModel.hx

import bindx.IBindable;

class UserModel implements IBindable
    public var name:String;
    public var coins:Int;

    public var health:Float = 1;

    public function new(name:String, coins:Int) {
        this.name = name;
        this.coins = coins;


// bind complex expression with another field
unbindOldUser = BindExt.exprTo('Hello ${user.name}. You have ' + user.coins + " coins", this.textField.text);

// listen field changes
Bind.bind(user.health, onHealthChange);

function onHealthChange(from:Null<Float>, to:Null<Float>) {
    trace('user health changed from $from to $to');

All examples



Method Description
Bind.bind(expr, listener) executes listener if property or method in expr was changed. If expr contains property, then listener accepts 2 arguments: old and new values. If expr contains method, listener accepts no arguments. Use Bind.unbind for unbind
Bind.bindTo(expr, toExpr) Assign result of expr to toExpr (NB: if expr contains method, then this method will be executed without arguments!). Does NOT invoke expr automatically. Returns reference callback, which can be used to unbind.
Bind.notify(expr, oldValue, newValue) Manually execute notification about property or method changes (if expr is method, then oldValue and newValue are not required)
Bind.unbind(expr, listener) Unsubscribe provided listener from expr changes (NB: if listener is not specified, all listeners for binded to this expr will be unsubscribed)
Bind.bindAll(obj:IBindable, listener, force) listener(name:String, oldValue:Dynamic, newValue:Dynamic):Void Bind all properties and methods of obj (force mode instantiate all lazy signals). Return unbind callback
Bind.unbindAll(obj:IBindable) Unbind all properties and methods of obj (NB: still can bind new listeners after that!)

Extended API:

Method Description
BindExt.chain(chainExpr, listener) Subscribe to sequence of invokations like a.b.c(1).d.., fires signal if any member of chainExpr was changed (automatically unsubscribes from old value and subscribes to new one). Methods can be specified with arguments. (NB: for the first time listener will be called automatically). listener behaves identicaly to listener in Bind.bind(). BindExt.chain() chainExpr.
BindExt.chainTo(chainExpr, toExpr) Bind chainExpr to toExpr. (NB: for the first time binding is executed automatically). Returns a callback to unbind chainExpr.
BindExt.expr(expr, listener) Universal method. expr can be any valid Haxe expression. All IBindable instances and bindables properties will be found automatically. listener always accepts 2 arguments. Previous values automatically stored for methods. (NB: for the first time listener is called automatically). BindExt.expr() returns a callback to unbind expr.
BindExt.exprTo(expr, toExpr) Bind any valid expr to toExpr. (NB: for the first time listener is called automatically). Returns a callback to unbind expr.


bindx.IBindable and @:bindable meta:

Bindx will process special meta - @:bindable. If @:bindable is set for the whole class then it will be inherited by all public properties which don't have this meta already. @:bindable only processed for classes and interfaces which implement bindx.IBindable.

Accepts additional arguments: @:bindable(paramName1 = value, paramName2 = value ...), short notation paramName equals with paramName = true

Parameter Default value Description
inlineSetter false Whether to add inline accessor to automatically generated setters or not.
force false Special mode to ignore other arguments. Creates signal for notifications, but does not create or modify setters, so developer can manage signal firing manually using Bind.notify. Also force mode extends list of allowed properties if setter is null, never or dynamic (without force mode binding such properties is impossible because setters cannot be generated or modified automatically).
lazySignal true Whether to create notification signal immediately or wait till the first request. (By default: wait for request).
inlineSignalGetter false if lazySignal is true, add inline accessor to automatically generated getter.



-D bindx_log=LOG_LEVEL

Log level Description
0 Do not log anything
1 Concise log (optimal). (NB: also enabled with shorten flag: -D bindx_log)
2 Full binding log (useful for debugging)



haxelib install bindx2



Define Description Default value
bindx_lazy_signal lazy signal initiazation. -D bindx_lazy_signal=0 disable option true
bindx_inline_signal_getter inline signal getter false
bindx_inline_setter inline autogenerated setter false



  • BindExt and this. Use this.bindableA.bindableB to listen changes of bindableA, not only bindableB