style attribute with emberjs - ember.js

Question

Is there a way to set css properties by using emberjs properties' auto binding ?
Something like:
<div {{bindAttr style="background-color: divColor;"}}>
...
</div>

Answer 1

Please note that as of ember 1.13. binding attributes (bind-attr) is deprecated. You would need to use code similar to this to bind to the class:
<div class={{myClass}}></div>
Furthermore, style binding in this fashion is not recommended because it can introduce XSS vulnerabilities. The HTML templating automatically escapes HTML to prevent XSS when using {{...}}, but style attributes have additional vulnerabilities outside of the scope of the built-in escaping.
The recommended approach is to escape the CSS yourself (i.e. creating the escapeCSS function that would escape the specific CSS appropriately to prevent XSS - this is not a built-in function. You could start with Ember.Handlebars.Utils.escapeExpression and add any additional checking from that base.) More information can be found here:
https://guides.emberjs.com/v2.2.0/templates/writing-helpers/#toc_escaping-html-content
Then you tell Ember that the string is "safe" by using Ember.String.htmlSafe, and Ember will not try to escape that content.
controller:
myStyle: Ember.computed('color', function() {
var color = escapeCSS(this.get('color'));
return new Ember.String.htmlSafe("color: " + color);
})
template:
<div style={{myStyle}}></div>
Reference: http://emberjs.com/deprecations/v1.x/#toc_binding-style-attributes

Answer 2

Another simple way to do this is to add a computed property to your model.
Model ----
App.Photo = Em.Object.extend(
objectId: null
url: ""
style: (->
"background-image:url('" + #get("url") + "')"
).property("url")
)
Template -----
{{#each item in App.photoController}}
<div {{bindAttr style="item.style"}}></div>
{{/each}}
I got this working, and seems to be the simplest way to go about it.

Answer 3

Not exactly like that but close. You'll have to build the style string yourself. Look at this jsFiddle.
App = Ember.Application.create();
/**************************
* Models
**************************/
/**************************
* Views
**************************/
App.View = Ember.View.extend({
style: function() {
return "background-color:" + this.get('color');
}.property('color').cacheable()
});
/**************************
* Controllers
**************************/
App.set('controller', Ember.Object.create({
color: "transparent",
red: function() {
this.set('color', 'red');
},
blue: function() {
this.set('color', 'blue');
},
style: function() {
return "background-color:" + this.get('color');
}.property('color').cacheable()
}));
/**************************
* App Logic
**************************/
$(function() {
template:
{{#view Ember.Button target="App.controller" action="blue"}}BLUE{{/view}}
{{#view Ember.Button target="App.controller" action="red"}}RED{{/view}}
{{#view App.View colorBinding="App.controller.color" attributeBindings="style"}}
Color is {{App.controller.color}}
{{/view}}
<hr>
<div {{bindAttr style="App.controller.style"}}>And another way...</div>

Answer 4

Recent Ember version (2.3.0 as of this writing) allows straight-forward embedding of computed style.
// bar-graph.js
import Ember from 'ember';
export default Ember.Component.extend({
classNames: ['bar-graph'],
inlineStyle: Ember.computed('attrs.min', 'attrs.max', 'attrs.value', function() {
let min = this.get('attrs.min');
let max = this.get('attrs.max');
let value = this.get('attrs.value')
let percentage = Math.round(value / (max - min) * 100);
return new Ember.Handlebars.SafeString(`width: ${percentage}%`);
})
});
<!-- bar-graph.hbs -->
<div class="bar" style={{inlineStyle}}>{{value}}</div>
Live example

Answer 5

I have tried using answer provided by #WallMobile, but it has some syntax issues. So this is the correct syntax to be used.
App.Photo = Em.Object.extend({
objectId: null,
url: "",
style: function() {
return "background-image:url('" + this.get("url") + "')"
}.property("url")
})

Answer 6

HTMLBars now lets you do this - upgrade to the latest ember/ember-cli to take advantage of the new stuff.

Answer 7

There's a new addon which allows you to declare styles as JS objects and bind them to your component's style attribute. Check out ember-computed-style
import computedStyle from 'ember-computed-style';
export default Ember.Component.extend({
style: computedStyle('backgroundStyle'),
attributeBindings: ['style'],
backgroundStyle: function(){
return {
backgroundColor: this.get('divColor')
};
}.property('divColor'),
divColor: 'red'
});
This will produce:
<div style="background-color:red;"></div>

Answer 8

Another approach you could use is CSS custom properties.
ember-cli-custom-properties is an Ember add-on that binds component properties to CSS custom properties (variables). Its fairly simple to use. Once you install the add-on, the add-on makes the customProperties and customPropertyBindings property available on the #ember/component class.
For example, you could turn the raw HTML above into a Ember component, and give it a class name.
import Component from '#ember/component';
export default Component.extend ({
classNames: ['my-component'],
// Map the backgroundColor attribute to a CSS custom property
customProperties: ['backgroundColor']
});
You can then reference this class name in the styles in for your application.
.my-component {
background-color: var(--background-color);
}
Lastly, just set the backgroundColor attribute on the component to your desired color.
{{my-component backgroundColor="red"}}