Investigate support for two-way scrollTop / scrollLeft binding using the scroll event.

When getObserver is called for an undefined property an instance of OoPropertyObserver is returned.

When the property later becomes defined and is not a primitive property (has a getter/setter), the incorrect observer type has already been returned to the templating system so property change events cannot be observed.

I'm thinking we should return an instance of a new class: UndefinedPropertyObserver. This new class would listen for the property to become defined using Object.observe. When this happens it would do the following:

1. call ObserverLocator.getObserver to retrieve the correct "actual" observer.
2. delegate the subscribe, getValue and setValue methods to the "actual" observer.
3. funnel any existing callbacks into the "actual" observer via it's subscribe method.

note: UndefinedPropertyObserver's setValue method would need to have special handling to ensure the appropriate observer is created and change events are published.

Edit
specifically talking about cases where Object.getOwnPropertyDescriptor returns undefined. (As opposed to cases where it returns {value: undefined, writable: true, enumerable: true, configurable: true})

When bind to attributes(one-way) there are a couple of options you can either bind with attr-name.bind="variable" (also tried one-way and one-time) or using interpolation attr-name="${variable}", either way though if you try to bind to a namespaced element such as xlink:href you currently get:

Uncaught NamespaceError: Failed to execute 'setAttributeNS' on 'Element': '' is an invalid namespace for attributes.

For have the following in a controller page.js:

export class page {
    constructor(){
        this.icon = 'blah';
    }
}

and the following in page.html:

<template>
  <svg class="icon ${icon}">
    <use xlink:href="${icon}"></use>
  </svg>
</template>

As I said either of the bind's above is throwing the given error. It appears that the bug is in property-observation, in that the observer is either setting to a raw attribute or a null namespaced attribute which is causing the error.

I am having issues with binding a value to the select when using optgroups

<select value.bind="selectedTheme">
    <optgroup repeat.for="theme of themes" label.bind="theme.name" >
        <option repeat.for="skin of theme.skins" value.bind="skin">
          ${skin}
        </option>
    </optgroup>
  </select>

I am trying to load the array from a json from the backend.
So in the VM the themes property is null at first . then i do a http.get , and only then is the array assigned to the themes , when i do that the items appear in the select just fine , but the current selected item won't work.

It does work if i assign an array in the view model itself without loading it from the server.

tested with version 0.4.1

If you have an <input type="text" value.bind="var1" /> inside a <form> tag with a <button type="reset"> to clear data it will not update view model bindings.

the idea is that sometimes we bind to a none existent property, and the logger should tell us that this property does not exist.

but one of the great things about Aurelia is that sometimes you want to bind to dynamic properties, so making this an optional flag in logging verbosity level or something would make it better.

If you call aurelia.withResources(DateFormatValueConverter), the ValueConverter convention kicks in and registers the converter with the name date-format.

The hyphenated name is incompatible with the parser. This kind of error will occur:

Parser Error: Unexpected token : at column 30 in [repo.updated_at | date-format:'MMMM Do YYYY, h:mm:ss a' ]

If I rename the converter to "DateformatValueConverter" and use "dateformat" instead of "date-format" in the binding expression everything works.

Not sure if the convention or the parser should change. Changing the convention to use camel-casing seems like it would be the most straight-forward code change.

Currently AccessKeyed sets up an observer for the property that accesses the object instance (scope.object) and the property that accesses the key value (scope.key) but it does not observe the object's property identified by the key.

The current behavior makes sense when the object is an array instance (although it's been argued that Aurelia should use dirty-checking in cases where AccessKeyed accesses an array).

Plunker demonstrating the issue (thanks @mattduffield)

We need to wrap the Aurelia observation in a more user-friendly API, for example, au.observe(obj, 'property', callback);

If an element has multiple custom attributes on it and a ref, there should be a way to get access to any of the custom attribute class instances. Allow ref.attribute-name="someIdentifier" to be used.

ModifyArrayObserver does not deliver change records on index and length assignments.

Example:

var foo = [1, 2, 3];

foo[1] = 9;
foo.length = 0;

When enabling options on an attached behaviour an exception is thrown when the attribute is being parsed.

The following example is trying to expose an option called replace, for the spinner attached behavior:

static metadata(){ return Behavior.attachedBehavior('spinner').withOptions().withProperty('value', 'valueChanged').withProperty('replace'); }

When the behavior above is used in a template, like so:

spinner.bind="value.bind: spinning; replace: true"

the parsing of the attribute fails, the stack trace is the following:

Potentially unhandled rejection [2] Error: Parser Error: Unexpected token : at column 11 in [value.bind: spinning; replace: true]
at ParserImplementation.error (http://localhost:9000/jspm_packages/github/aurelia/[email protected]/system/parser.js:470:21)
at ParserImplementation.parsePrimary (http://localhost:9000/jspm_packages/github/aurelia/[email protected]/system/parser.js:365:22)
at ParserImplementation.parseAccessOrCallMember (http://localhost:9000/jspm_packages/github/aurelia/[email protected]/system/parser.js:306:33)
at ParserImplementation.parsePrefix (http://localhost:9000/jspm_packages/github/aurelia/[email protected]/system/parser.js:297:29)
at ParserImplementation.parseMultiplicative (http://localhost:9000/jspm_packages/github/aurelia/[email protected]/system/parser.js:270:33)
at ParserImplementation.parseAdditive (http://localhost:9000/jspm_packages/github/aurelia/[email protected]/system/parser.js:252:33)
at ParserImplementation.parseRelational (http://localhost:9000/jspm_packages/github/aurelia/[email protected]/system/parser.js:230:33)
at ParserImplementation.parseEquality (http://localhost:9000/jspm_packages/github/aurelia/[email protected]/system/parser.js:208:33)
at ParserImplementation.parseLogicalAnd (http://localhost:9000/jspm_packages/github/aurelia/[email protected]/system/parser.js:194:33)
at ParserImplementation.parseLogicalOr (http://localhost:9000/jspm_packages/github/aurelia/[email protected]/system/parser.js:180:33)

I tried different combinations in the attribute content, but the parser apparently does not like the ':' character.

I`am trying to use click.trigger on button element which resides in div element which has click.event.stopPropagation, when I remove click.event.stopPropagation all is working well, but when it is present click.trigger do not work

Example

<template>
<div click.delegate="delegateMethod($event)">
  <h1>test .... CCC</h1>
  <input type="text" value.bind="stringValue"/>
  <button type="button" click.trigger="callMethod()">callMethod...</button>
</div>
</template>

export class Cc {
    stringValue:string='Init value...';

    delegateMethod($event) {
      $event.stopPropagation();
      alert('delegateMethod:' + this.stringValue);
    }
    callMethod() {
      alert('callMethod:' + this.stringValue);
    }
}

When the selected value of a <select> is bound to a property of a server-side fetched model, and the available options are fetched with another API call, Aurelia binding cannot know which is the selected option since it comes from a separate request and it's not a reference from the options array.

Is there a best practice to handle this?

Use case HTML:

<select value.bind="job.assignee">
    <option repeat.for="employee of employees" model.bind="employee">${employee.name}</option>
</select>

and JavaScript:

import {HttpClient} from 'aurelia-http-client';

export class Job {
    constructor() {
        this.http = new HttpClient();
    }
    activate(params) {
        return Promise.all([
            this.http.get('/api/jobs/' + params.id).then(http => {
                this.job = JSON.parse(http.response);
            }),
            this.http.get('/api/employees').then(http => {
                this.employees = JSON.parse(http.response);
            })
         ]);
     }
}

where the API request /api/jobs/:id returns:

{
    "id": 1234,
    "assignee": {
       "name": "Jack",
       "age": 20
    }
}

and the /api/employees returns:

[
   {
       "name": "John",
       "age": 28
    }, {
       "name": "Jack",
       "age": 20
    }
]

In this case the <select> initial value would be the first option John instead of the correct option Jack.

The following will fail.

<h2>${encodeURI(heading)}</h2>

Is this by design or a bug?

Stack trace is:

Potentially unhandled rejection [1] Error: encodeURI is not a function
    at ensureFunctionFromMap (http://localhost:9000/jspm_packages/github/aurelia/[email protected]/system/ast.js:58:13)
    at CallScope.evaluate (http://localhost:9000/jspm_packages/github/aurelia/[email protected]/system/ast.js:652:22)
    at CallScope.connect (http://localhost:9000/jspm_packages/github/aurelia/[email protected]/system/ast.js:692:29)
    at InterpolationBinding.connect (http://localhost:9000/jspm_packages/github/aurelia/[email protected]/system/binding-language.js:232:35)
    at InterpolationBinding.bind (http://localhost:9000/jspm_packages/github/aurelia/[email protected]/system/binding-language.js:201:22)
    at View.bind (http://localhost:9000/jspm_packages/github/aurelia/[email protected]/system/view.js:69:29)
    at RouterView.swap (http://localhost:9000/jspm_packages/github/aurelia/[email protected]/system/router-view.js:85:49)
    at http://localhost:9000/jspm_packages/github/aurelia/[email protected]/system/navigation-context.js:72:37
    at Array.forEach (native)
    at http://localhost:9000/jspm_packages/github/aurelia/[email protected]/system/navigation-context.js:71:28es6-module-loader.src.js:139 (anonymous function)es6-module-loader.src.js:166 fes6-module-loader.src.js:188 i

I'm trying to unit test a class that contains @bindable and whenever that variable is set I get the following error

Cannot read property 'getObserversLookup' of undefined

Is there some setup or initializations that needs to be performed for this to work.

basic example

import { bindable } from 'aurelia-framework';

class Example {
  @bindable example;

  constructor() {
  }

  test() {
    this.example = "something";
  }
}


describe('the Example module', () => {
  var example;

  beforeEach(() => {
    example = new Example();
  });


  it('demonstrate failure', () => {
    example.test();
  });
});

Cheers,
Ashley

When using a text input, If you use the value binding on an object that does not have the property on it, 'undefined' gets added into the input. Should this just be an empty string or throw an error?

e.g. model:

this.myModel = {
    name: ""
}

html:

<input  value.bind="myModel.name"  />

<input value.bind="myModel.doesNotExist" />

related to aurelia/skeleton-navigation#85

If you have a table in which some columns are shown based on some condition, both the show.bind and if.bind fail to behave properly on TD cells in particular and they also behave differently.

The following code case shows this:

http://plnkr.co/edit/NSgsbS?p=preview

Some examples where this is of value include:
Table view configurations
Toggling columns on or off based on a condition or the data type
Hiding columns based on available real estate (adaptive column models)

when bind "click.delegate" to checkbox input element, ui element can not follow the checked value, always show uncheck state

    <input id="toggleAll" type="checkbox" click.delegate="toggleAll();" >

if delete the code [ click.delegate="toggleAll();" ], the ui state is correct!

Given the following custom element template...

<!-- svg.class="search" -->
<template>
  <svg role="img" class="${svg.class}">
    ...
  </svg>
</template>

The rendered output is as follows...

<svg role="img" class="${svg.class} au-target" className="search">
    ....
</svg>

Notice that ${svg.class} is still present in the class attribute of the svg tag and the values that should have replaced ${svg.class} have instead been added to a separate attribute called className. The expected behaviour is that the value of svg.class should be added to the class attribute of the svg tag.

When I use xxxx.two-way I get the Observation of an Element's "xxxx" is not supported. error.
Is there any kind of restriction for what properties can we bind to? I tried this with a polymer custom element so if there is a white list of properties that can be two way bound I suggest looking into the properties in the prototype of the element and allow binding on those.

It's not possible to get an observerlocator on an @bindable property:

@inject(ObserverLocator)
export class Welcome{
  heading = 'Welcome to the Aurelia Navigation App!';
  @bindable firstName = 'John';
  lastName = 'Doe';

  constructor(observerLocator)
  {     
    //var me = this['firstName']; 
    var a = observerLocator.getObserver(this, 'firstName');
    var d = a.subscribe(()=>{});
    debugger;
  }

This throws
heckProperty.getValue (http://localhost:9000/jspm_packages/github/aurelia/[email protected]/dirty-checking.js:77:26) {innerError: RangeError: Maximum call stack size exceeded, stack: (...), message: "Error instantiating Welcome.↵---------------------…ub/aurelia/[email protected]/dirty-checking.js:77:26)"}innerError: RangeError: Maximum call stack size exceededmessage: "Error instantiating Welcome.↵------------------------------------------------↵inner error: RangeError: Maximum call stack size exceeded↵ at Welcome.execute.BindableProperty.configureDescriptor.descriptor.get as firstName↵ at DirtyCheckProperty.getValue (http://localhost:9000/jspm_packages/github/aurelia/[email protected]/dirty-checking.js:77:26)↵ at Welcome.execute.BindableProperty.configureDescriptor.descriptor.get as firstName↵ at DirtyCheckProperty.getValue (http://localhost:9000/jspm_packages/github/aurelia/[email protected]/dirty-checking.js:77:26)↵ ...

If I 'resolve' the property before gettting the observer, by uncommenting the line

var me = this['firstName']; 

Then everything works as expected.

discussion on gitter chat

Currently, every event is default prevented by default. This breaks the desired behavior of certain events like dragstart. We'd like a way to tell the event handler to allow default behavior. The best way to handle this might be to allow default if the event returns true.

https://github.com/aurelia/binding/blob/master/src/dirty-checking.js#L79 This code always returns false when checking for arrays(properties who's getter returns an array in view-model).

This makes Aurelia to constantly update the DOM as if in an infinite loop.

Isn't there a necessity to deep compare ?

this options as far as i understand enables us to have multi properties in attached behavior.

but currently there is no documentation on the syntax and how it works.

thanks in advanced.

@EisenbergEffect Thoughts on what the binding expressions would look like?

Knockout style ?

Or what if the framework had attached behaviors built from the first column of this list (maybe prefixed with css- or style-):

https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_Properties_Reference

Assign to me if you want.

In app-contacts you can do

<a href="#" click.delegate="$parent.select(contact)">
</a>

where you can pass view scoped arguments like contact

If I have a custom behavior I can't do the same

<div oribella-tap="end.call: onTap(e,data,contact);"></div>

where e and dataare behavior scoped and contact view scoped. It would be nice if the CallExpression could support evaluating behavior scoped properties somehow.
Let me know if you need more info.

Hi there,

Rob asked me to post this issue -- it'd be nice if there was a way to natively bind key pressed events to HTML elements in the Aurelia binding framework. For example, if enter is pressed on an input text box, Aurelia delegates to a function in the ViewModel to execute some work.

He also mentioned the current workaround is to create an Attached Behavior, exposing the event that can be delegated to a function in the ViewModel. I wracked my brain for a little bit trying to figure it out, but came up blank. Would you happen to have a snippet I can work off of?

I'm guessing the implementation on the HTML side may look something like this with the attached behavior approach?

<input type="text" enter-key-pressed.bind="enterKeyPressed()" />

Thanks!

Eric

@Alxandr and I were brainstorming how to get around using dirty-checking when binding computed properties (properties that have a getter function).

One idea we were throwing around was to provide a way declare the computed property's dependencies. This way aurelia could observe the computed property's dependencies and recompute the property value only when the dependencies change. If this isn't something that should be put in Aurelia directly an adapter could provide this logic (#10).

Thoughts?

First attempt (no worky):

var person = { firstName: 'Don', lastName: 'Draper' };

Object.defineProperty(person, 'fullName', {
  enumerable: true,
  configurable: true,
  get: function() { return this.firstName + ' ' + this.lastName; },
  dependencies: ['firstName', 'lastName']  // wondering if getOwnPropertyDescriptor will return this...
});


var descriptor = Object.getOwnPropertyDescriptor(person, 'fullName');
descriptor.dependencies  // undefined :(  bummer....

Second Attempt (works but not ES6 style/if-stmt in getter is bad idea)

var person = { firstName: 'Don', lastName: 'Draper' };

Object.defineProperty(person, 'fullName', {
  enumerable: true,
  configurable: true,
  get: function(returnDependencies) {
    if (returnDependencies)
      return ['firstName', 'lastName'];    
    return this.firstName + ' ' + this.lastName; 
  }
});


var descriptor = Object.getOwnPropertyDescriptor(person, 'fullName');
descriptor.get(true);

Third Attempt (works but ugly/even worse)

var person = { firstName: 'Don', lastName: 'Draper' };
function fullName() {
  return this.firstName + ' ' + this.lastName; 
}

fullName.dependencies = ['firstName', 'lastName'];

Object.defineProperty(person, 'fullName', {
  enumerable: true,
  configurable: true,
  get: fullName
});

var descriptor = Object.getOwnPropertyDescriptor(person, 'fullName');

descriptor.get.dependencies;
// ["firstName", "lastName"]

Last Attempt

function declarePropertyDependencies(ctor, propertyName, dependencies) {
  var descriptor = Object.getOwnPropertyDescriptor(ctor.prototype, propertyName);
  descriptor.get.dependencies = dependencies;
}

export class Person {
  constructor() {
    this.firstName = 'Don';
    this.lastName = 'Draper'; 
  }

  get fullName() {
    return this.firstName + ' ' + this.lastName;
  }
}

declarePropertyDependencies(Person, 'fullName', ['firstName', 'lastName']);

Variation of last attempt, enabling multiple props to be configured in one call

function markComputedProperties(object, props) {
  var keys = Object.keys(props);
  for (var i = 0, l = keys.length; i < l; ++i) {
    var descriptor = Object.getOwnPropertyDescriptor(object.prototype, key);
    descriptor.get.dependencies = props[key];
  }
}

export class Person {
  constructor() {
    this.firstName = 'Don';
    this.lastName = 'Draper'; 
  }

  get fullName() {
    return this.firstName + ' ' + this.lastName;
  }
}

markComputedProperties(Person, {
  fullName: ['firstName', 'lastName']
});

The AST evaluation for AccessMember can break if the member is undefined rather than null.

<form> 
  <input type="text" value.bind="val" />
  <input type="reset" />
</form>

Clicking the reset button does not update the value of val.

https://gitter.im/Aurelia/Discuss?at=54f2f35e0cfa7291277d01e4

What do we want the binding syntax to look like:

<td contenteditable="true" inner-html="value.two-way: tdtext;"></td>

or this:

<td contenteditable="true" value.bind="tdtext"></td>

Test fiddle for contenteditable element events:
http://jsfiddle.net/8j6jea6p/

Parser.js breaks under minification. I have yet to be able to figure out exactly what goes wrong, but it's in the constructor of the Parser class.

Here is the minified code that goes wrong

function e(){this.cache={},this.lexer=new t}

The error that get's throw is

TypeError: Cannot set property 'cache' of undefined

Will do some more investigating.

We need to ensure that we support as many attributes available in SVG as possible. Here's some documentation that lists attributes: http://www.w3.org/TR/SVG/attindex.html We need to add any camel cased attributes to our mapping.

I want to write a modular system so that designers can build stuff with out having to write code. To do this I created a non visual custom element that calls a service to fetch work orders. internally it has a @bindable property called workorders.

using the control in a view that also has a bindable property called workorders, the work orders are fetched but the value does not bubble up to the view.

<get-workorders workorders.two-way="workorders" auto.bind="true"></get-workorders>

what I want to be able to do is this.

<get-workorders workorders.two-way="workorders" />
<show-workorders workorders.bind="workorders" />

when I make get-workorders a visual control by adding a template and removing the noView decorator, then the two way binding works as expected.

Summary:
Two way binding should work with a custom element that is noView

If the viewmodel has a property called for example 'förnamn' and tries to bind to it the lexer can't handle the charachter 'ö'. This is probably true for other international charachters too like 'å' and 'ä'.

In the skeleton-navigation example app some text is bound to an es5 property

<div class="form-group">
    <label>Full Name</label>
    <p class="help-block">${fullName | upper}</p>
</div>

export class Welcome{
  constructor(){
    this.heading = 'Welcome to the Aurelia Navigation App!';
    this.firstName = 'John';
    this.lastName = 'Doe';
  }

  get fullName(){
    return `${this.firstName} ${this.lastName}`;
  }
  ...
}

When I run the app (in chrome) I can see that the fullName getter is called roughly every 120ms, despite nothing changing. So it appears to be 'falling back' to dirty-checking. Is this the expected behaviour, and is there another way to write this code so that the binding uses one of the more efficient binding mechanisms?

Currently there's no way to reference the view-model itself from the view, and can currently only reference its properties. A way to reference the VM as a whole would be great. Currently the only way to do this is to create a property on the view model to reference itself.

Eg:

export class EntityTreeView {
    constructor(modelFactory) {
        this.treeRoot = this;
    }

    doSomethingWithNode(node) {
        something(node);
    }
}

<component model.bind="{ node: nodes, root: treeRoot }"></component>

Use case:

Trying to build out a tree, so we recursively build out each node. When the node gets clicked it needs to call a function at the root level of the tree. Don't want to have to use EventAggregator to do so.

Strange but when I looked through the ES6 sources of dirty-checking.js I see that line transpiled to this https://github.com/aurelia/binding/blob/master/dist/system/dirty-checking.js#L43.

The this.checkDelay over here does not point to the DirtyChecker class and should have been _this.checkDelay

If i have

<div class="todo-card" class.bind="todo.completed ? 'completed' : ''"></div>

I expect that the div either becomes

<div class="todo-card completed">

or

<div class="todo-card">

Currently it becomes

<div class="completed">

or

<div class="">

I'm not sure this would be the expected behavior. I would not want to do

<div class="todo-card ${todo.completed ? 'completed': ''}"> 

in a lot of cases

related to aurelia/templating-resources#21

In this case the options are static but each option's value/model are data bound.

view-model:

this.value = true;

view:

  <select value.bind="value">
    <option model.bind="null">null</option>
    <option model.bind="false">false</option>
    <option model.bind="true">true</option>
  </select>

The select-value binding happens before the model bindings on the options. Since these bindings don't mutate the dom, the mutation-observer used in aurelia/templating-resources#21 doesn't help.

Writing tests for the fix... will submit PR.

viewModel
array = ['foo']

view
<div>${array[0]}</div>

The above will output foo, as expected. However, if you index-assign a new value, e.g. array[0] = 'bar', the output is not updated.

https://developer.mozilla.org/en-US/docs/Web/HTML/Element/datalist

<div>Choose a browser from this list:</div>
<input list="browsers" />
<datalist id="browsers">
  <option value="Chrome">
  <option value="Firefox">
  <option value="Internet Explorer">
  <option value="Opera">
  <option value="Safari">
</datalist>

Question came up in the gitter around binding an input's value to an object when using <datalist>. Each option in the datalist was using model.bind.

If you delegate an event using the $parent scope, for example <button click.delegate="$parent.click()"></button>, this.$event is undefined within the click() function. In fact, the event is not available to such a handler at all. We would expect this.$event to be defined within every click handler, regardless of the scope.

It is easy for a dev to accidentally click.bind="" on accident. Let's let them know when they make easy mistakes.

aurelia.io is lacking documentation on radio and checkbox binding

Enhancement - add debounce to binding options.

Say we have an input such as -

<input value.bind="searchCriteria" onChange.bind="callServer" />

Where we want an event to take place that calls the remote server, but only after a specified amount of time, in this case 1000 milliseconds -

<input value.bind="searchCriteria" change.bind="callServer -debounce=1000" />