Aurelia oneTime绑定为defaultBindingMode

Question

I am trying to do something like this:

bindable({defaultBindingMode: bindingMode.oneTime}) options = {};

and getting a warning in the browser's console:

WARN [templating-binding] Unknown binding command. Object {defaultBindingMode: 1, attrName: "route-href", attrValue: "navModel.config.name", command: "onetime", expression: null}

Shouldn't I be able to specify that the options parameter (which is really only used once in attached() ) should only be bound one time by default?

Answer 1

You can't use the inline syntax of bindable in the way you're attempting. You need to use the more verbose syntax and decorate the class.

@bindable({
    name: 'options',
    defaultBindingMode: bindingMode.oneTime,
    defaultValue: {}
});
export class MyViewModel {
...
}

The syntax for @bindable is as follows (right from the documentation):

@bindable({
  name:'myProperty',
  attribute:'my-property',
  changeHandler:'myPropertyChanged',
  defaultBindingMode: bindingMode.oneWay,
  defaultValue: undefined
})

Answer 2

You have to use it this way;

import {bindable} from 'aurelia-framework'
import {bindingMode} from 'aurelia-binding'

@bindable({name:'foo', defaultBindingMode : bindingMode.oneTime})
export class Elem{
  foo;
}

Or you can do it in-line:

import {bindable} from 'aurelia-framework'
import {bindingMode} from 'aurelia-binding'

export class Elem{
  @bindable({name:'foo', defaultBindingMode : bindingMode.twoWay}) foo;
}

Here is a plunker with the code that should work. But there is a bug at this, oneTime is ignored when used as a defaultBindingMode . See this issue I have just reported.