# Boolean component attributes in attrs-hash

**URL:** <https://discuss.emberjs.com/t/boolean-component-attributes-in-attrs-hash/8029>\
**Category:** Uncategorized\
**Created:** [May 18, 2015, 9:11am UTC](https://discuss.emberjs.com/t/boolean-component-attributes-in-attrs-hash/8029 "2015-05-18T09:11:08Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![francesconovy](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.emberjs.com/francesconovy/32/9607_2.png) [@francesconovy](https://discuss.emberjs.com/u/francesconovy)\
**Post date:** [May 18, 2015, 9:11am UTC](https://discuss.emberjs.com/t/boolean-component-attributes-in-attrs-hash/8029/1 "2015-05-18T09:11:08Z")

</div>

When using the new attrs: {} hash in components with Ember 1.13.0-beta.1, boolean values are treated somehow strange.

If I have a controller with the property `controllerOpen: true`, and in the template I have something like this: `{{test-component open=controllerOpen}}`, then the usage of `attrs.open` is not entirely clear - it is not a boolean, but an object? Which means that something like `this.toggleProperty("attrs.open");` does not work as expected.

In order to show what I mean, I made a quick jsbin: [http://emberjs.jsbin.com/togidogune/2/edit?html,js,output](http://emberjs.jsbin.com/togidogune/2/edit?html,js,output)

In the example, I can either change the attribute in the component, or in the controller. When I change it in the controller, it works as expected, but when I change it in the component, it doesn’t. In the console, you can see the actual value of attrs.open.

Is there a reason why boolean attributes are passed in as objects? In my opinion, this is very unintuitive - how am I supposed to change the boolean attribute from inside of the component?

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<div class="post-metadata">

**Author:** ![rwjblue](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.emberjs.com/rwjblue/32/9411_2.png) [@rwjblue](https://discuss.emberjs.com/u/rwjblue)\
**Post date:** [May 18, 2015, 10:52am UTC](https://discuss.emberjs.com/t/boolean-component-attributes-in-attrs-hash/8029/2 "2015-05-18T10:52:59Z")

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In Ember 1.13 the following:

```handlebars
{{some-thing name=localProperty}}

```

Is automatically translated to the following during template compilation:

```handlebars
{{some-thing name=(mut localProperty)}}

```

* * *

For SemVer/backward compatibility reasons Ember 1.x must continue to have mutable two-way bindings enabled by default. This means that every bound property path from a template invocation (like `name` in the example above) is transformed into a “mutable object”. A mutable object has a `value` property and an `update` method (the `update` method is how it can be set and cause upward data flow). When you access the attribute in the `.attrs` hash, you are “seeing” the mutable object.

* * *

Because this is somewhat odd (did I get a mutable object? do I need to call `this.attrs.name.value` or just `this.attrs.name`? etc), there is a new public API to return the attribute value (mostly useful for the 1.x timeframe while we do the auto-wrapping). To use this, you simply do `this.getAttr('name')`, if `this.attrs.name` was a mutable value then it will return `this.attrs.name.value` otherwise it returns `this.attrs.name`.

* * *

FYI - For angle bracket components (and likely all components in Ember 2.0) you will be required to use the `(mut)` sub-expression to explicitly provide a mutable value.

* * *

Docs and guides are being written to make this _much_ clearer, but hopefully, this “dump” was helpful to folks in the interim…

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<div class="post-metadata">

**Author:** ![francesconovy](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.emberjs.com/francesconovy/32/9607_2.png) [@francesconovy](https://discuss.emberjs.com/u/francesconovy)\
**Post date:** [August 17, 2015, 7:23am UTC](https://discuss.emberjs.com/t/boolean-component-attributes-in-attrs-hash/8029/3 "2015-08-17T07:23:38Z")

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Has there been any progress in the docs for this? I was just looking through the 2.0 docs for components etc. and couldn’t find any references about how to use attrs.

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<div class="post-metadata">

**Author:** ![Kerrick](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.emberjs.com/kerrick/32/14915_2.png) [@Kerrick](https://discuss.emberjs.com/u/Kerrick)\
**Post date:** [December 15, 2015, 9:31pm UTC](https://discuss.emberjs.com/t/boolean-component-attributes-in-attrs-hash/8029/4 "2015-12-15T21:31:39Z")

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Is `this.getAttr('name')` an officially supported method going forward? It’s not in the docs for 1.13.x or even 2.2.x. Is this something we should feel safe using?