javascript - Need for value attribute in directive 'scope' - Stack Overflow

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I was going through the process of creating a directive. Having gone through a few ups and downs I got through creating the directive ( widget ) and was finalizing the various attributes the directive will take.

I used the various options available like attribute, bind, evaluate, expression etc..

What I figured was that if you want to create a generic ponent, you can never tell how people will pass values to the the ponent.

Here is an illustration...

You are creating a new element ponent.. say

<hello name="__ARGUMENT__"></hello>

The name attribute for hello is the only variable in it. If you give it out to the public... these are the possible scenarios with which people may use this ponent.

case 1 :

<hello name="angular"></hello>

case 2 :

<hello name="{{name}}"></hello> 

case 3 :

<div ng-repeat="name in names">
    <hello name="name"></hello> 
</div>

Now.. for different scenarios.. I have e to understand the various options provided. I cant think of a single scenario where you would ever want the 'attribute' since its a simple direct substitution of values from ponent to the template..

In your directive definition if you had defined the name as 'evaluate' instead of 'attribute'

if attribute :

<hello name="angular"></hello>

if evaluate :

<hello name="'angular'"></hello>

note the extra single quotes..

So as far as I can tell evaluate covers what attribute does.. And, using evaluate seems to be a better choice than just attribute since it covers more scenarios!

If someone can explain why attribute exists in the first place? More choices = more confusion.. :)

I was going through the process of creating a directive. Having gone through a few ups and downs I got through creating the directive ( widget ) and was finalizing the various attributes the directive will take.

I used the various options available like attribute, bind, evaluate, expression etc..

What I figured was that if you want to create a generic ponent, you can never tell how people will pass values to the the ponent.

Here is an illustration...

You are creating a new element ponent.. say

<hello name="__ARGUMENT__"></hello>

The name attribute for hello is the only variable in it. If you give it out to the public... these are the possible scenarios with which people may use this ponent.

case 1 :

<hello name="angular"></hello>

case 2 :

<hello name="{{name}}"></hello> 

case 3 :

<div ng-repeat="name in names">
    <hello name="name"></hello> 
</div>

Now.. for different scenarios.. I have e to understand the various options provided. I cant think of a single scenario where you would ever want the 'attribute' since its a simple direct substitution of values from ponent to the template..

In your directive definition if you had defined the name as 'evaluate' instead of 'attribute'

if attribute :

<hello name="angular"></hello>

if evaluate :

<hello name="'angular'"></hello>

note the extra single quotes..

So as far as I can tell evaluate covers what attribute does.. And, using evaluate seems to be a better choice than just attribute since it covers more scenarios!

If someone can explain why attribute exists in the first place? More choices = more confusion.. :)

• javascript
• angularjs

Share Follow edited Oct 30, 2014 at 15:20 Rahil Wazir 10.1k1111 gold badges4444 silver badges6565 bronze badges asked May 30, 2012 at 13:04 GanarajGanaraj 26.8k66 gold badges6767 silver badges6060 bronze badges 1

• Ganaraj, it's great that you've brought this up. As I was reading through the directive doc this weekend, I came to similar conclusions. One other thing is the controller "require" attribute with the magic literal prefixes (?,^). The fact that ? makes the require dependency optional is a bit strange. Maybe have separate options, which of course plicates things more... – Dan Doyon Commented May 30, 2012 at 19:14

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1 Answer 1

Sorted by: Reset to default 7

We are well aware of this confusion, and will be cleaning it up in the future.

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