Angular Elements - Additional Attribute Bindings

Question

Angular Elements - Additional Attribute Bindings

My goal is to create a series of versatile components (angular 1.5) with various optional bindings that can be utilized in multiple applications.

I am concerned about the potential creation of unnecessary watchers for an application that does not utilize most of the optional bindings.

For example:

Component declaration:

let dateRangeComponent = {
    bindings: {
        label: '@',
        name1: '@',
        name2: '@',
        model1: '>?',
        model2: '>?',
        extra1: '>?'
    },
    template: `<div ng-if="$ctrl.model1>stuff</div>
               <div ng-if="$ctrl.model2>stuff</div>
               <div ng-if="$ctrl.extra1>stuff</div>`
};

Example of Component usage:

<date-rage-component label="Pretty Date" name1="Start" name2="end"/>

Is there a way to automatically stop watching the unused optional bindings, considering they are undefined during compilation?

For instance, if I want to use a component in an application where none of the optional bindings are required, Angular would still create excessive watchers to update ng-if statements that will always evaluate to false.

Am I prematurely optimizing for performance unnecessarily or misunderstanding a concept?

I have considered creating a custom wrapper directive to leverage lazy transclude compilation in angular 1.5

Here is some pseudo-code I came up with:

<optional-binding-once ng-if="::attrs.model1">
  <div ng-if="attrs.model1">
      stuff
  </div>
</optional-binding-once>

This approach aims to compile the code inside optional-binding-once only when ng-if evaluates to true, thereby reducing the number of watchers if a binding is not defined.

(EDIT) Some Insights after conducting tests and research

It appears that there is no straightforward solution to minimize the watcher count within a component when optional bindings are left unfilled.

I ran some tests during the $digest phase of Angular to determine if the increased number of such watchers poses a real issue.

Below are my findings:

The tests were carried out under a worst-case scenario involving 888 components with 4 optional bindings each.

Chrome - Without optional bindings ( 888 component, total watchers 889)

Total Watchers: 889
Last Digest Cycle time: 0.9950000000026193
Average time for the last 1004 digest cycles: 1.0544920318724353 ms
Starting DOM loading (400ms)

Chrome - With optional bindings ( 888 component, 4 optional bindings, total watchers 4441)

Total Watchers:4441
Last Digest Cycle time: 1.1549999999988358
Average time for the last 1001 digest cycles: 1.6851748251747816 ms
Starting DOM loading (600ms)

Safari - Without optional bindings ( 888 component, total watchers 889)

Total Watchers: 889
Last Digest Cycle time: 1.0849999999991269
Average time for the last 530 digest cycles: 1.211632075471664 ms

Safari - With optional bindings ( 888 component, 4 optional bindings, total watchers 4441)

Total Watchers: 4441
Last Digest Cycle time: 1.7450000000026193
Average time for the last 588 digest cycles: 2.1167176870748237 ms

Conclusions:

In a worst-case scenario, an increase of 1ms in the $digest time is observed. This elevation does not seem to pose a significant bottleneck in application performance. These types of watchers fail at the first condition of $digest (value = get(current)) !== (last = watch.last) && etc...), thus having minimal impact on processing time as they remain unchanged and do not affect the Angular context!

javascript angularjs angularjs-directive

Answer 1

Answer №1

To make use of the dynamic capabilities of the template property, I would leverage the fact that it can accept a function as a value (documentation). This function could then manipulate the template based on the provided attributes.

My approach would involve using jQuery and custom elements to mark conditional sections within the template.

Below is an example of how the template function could look like:

function template($element, $attrs) {
  var fullTemplate = $('<div><if-attr name="a"><div ng-if="$ctrl.a"></div></if-attr></div>');
  fullTemplate.find('if-attr').each(function() {
    if (attrs.hasOwnProperty($(this).attr('name'))) {
      $(this).replaceWith(this.innerHTML);
    } else {
      $(this).remove();
    }
  });
  return fullTemplate[0].outerHTML;
}

Example Output

template(null, {a: '1'}) =>

"<div><div ng-if="$ctrl.a"></div></div>"

template(null, {b: '1'}) => "<div></div>"

Potential Limitations

One limitation to keep in mind is that this method may not work seamlessly if you need to retrieve the template from a URL (and it's not already cached in the $templateCache). However, based on your scenario, this should not be an issue.

Considerations for Minification

The AngularJS documentation mentions that when defining the template as a function, it will be injected with $element and $attrs. To ensure proper functionality after minification, it's important to specify minification-safe parameter names for the function.

template: ['$element', '$attrs', function ($elem, $attrs) { 
    // ...
}],

or

function templateFn($elem, $attrs) { 
    // ...
}
templateFn['$inject'] = ['$element', '$attrs'];

template: templateFn,

Answer 2

To make use of the dynamic capabilities of the template property, I would leverage the fact that it can accept a function as a value (documentation). This function could then manipulate the template based on the provided attributes.

My approach would involve using jQuery and custom elements to mark conditional sections within the template.

Below is an example of how the template function could look like:

function template($element, $attrs) {
  var fullTemplate = $('<div><if-attr name="a"><div ng-if="$ctrl.a"></div></if-attr></div>');
  fullTemplate.find('if-attr').each(function() {
    if (attrs.hasOwnProperty($(this).attr('name'))) {
      $(this).replaceWith(this.innerHTML);
    } else {
      $(this).remove();
    }
  });
  return fullTemplate[0].outerHTML;
}

Example Output

template(null, {a: '1'}) =>

"<div><div ng-if="$ctrl.a"></div></div>"

template(null, {b: '1'}) => "<div></div>"

Potential Limitations

One limitation to keep in mind is that this method may not work seamlessly if you need to retrieve the template from a URL (and it's not already cached in the $templateCache). However, based on your scenario, this should not be an issue.

Considerations for Minification

The AngularJS documentation mentions that when defining the template as a function, it will be injected with $element and $attrs. To ensure proper functionality after minification, it's important to specify minification-safe parameter names for the function.

template: ['$element', '$attrs', function ($elem, $attrs) { 
    // ...
}],

or

function templateFn($elem, $attrs) { 
    // ...
}
templateFn['$inject'] = ['$element', '$attrs'];

template: templateFn,

Answer 3

Answer №2

To elevate your code quality, consider avoiding the creation of a one-size-fits-all component. Instead, delegate the business logic to services and craft specific components tailored to each unique need. Empower consumer code to select the appropriate component based on their requirements. If you find yourself with similar functionalities shared among various components, leverage service injection for reusability. Opt for breaking down the business logic into distinct services and employ a hierarchical approach to reuse code while allowing for customization when needed. Centralize shared functionalities within an abstract service, then extend them into concrete services. Inject these concrete services into your components for enhanced efficiency. Stay positive and happy coding :).

Answer 4

To elevate your code quality, consider avoiding the creation of a one-size-fits-all component. Instead, delegate the business logic to services and craft specific components tailored to each unique need. Empower consumer code to select the appropriate component based on their requirements. If you find yourself with similar functionalities shared among various components, leverage service injection for reusability. Opt for breaking down the business logic into distinct services and employ a hierarchical approach to reuse code while allowing for customization when needed. Centralize shared functionalities within an abstract service, then extend them into concrete services. Inject these concrete services into your components for enhanced efficiency. Stay positive and happy coding :).

Answer 5

Answer №3

If you want to avoid multiple watchers and ensure better performance, simply use one-time binding with {{::variable}}.

Answer 6

If you want to avoid multiple watchers and ensure better performance, simply use one-time binding with {{::variable}}.

Answer 7

Answer №4

Make sure to dismantle the component binding once you've made a call to the component.

If you require further information, please verify and inform me.

https://example.com/angular-1-5-lifecycle-hooks#using-ondestroy

Answer 8

Make sure to dismantle the component binding once you've made a call to the component.

If you require further information, please verify and inform me.

https://example.com/angular-1-5-lifecycle-hooks#using-ondestroy

Answer 9

Answer №5

One clever approach is suggested by @GregL, which involves using a different template with unique attributes. Alternatively, you can also utilize the

ng-attr-[nameCustomAttr]="value"

syntax for optional bindings. Check out my relevant response for more insights on this topic. This allows Angular to optimize performance by utilizing a type of bindingOnce mechanism to determine whether or not an attribute should be added based on its value.

It's important to keep these attributes within the template of the directive/component for this method to work effectively.

Note: AngularJS will only create watches for variables that are displayed in the user interface.

Best of luck with implementing this technique - I hope it proves to be beneficial for your project.

Answer 10

One clever approach is suggested by @GregL, which involves using a different template with unique attributes. Alternatively, you can also utilize the

ng-attr-[nameCustomAttr]="value"

syntax for optional bindings. Check out my relevant response for more insights on this topic. This allows Angular to optimize performance by utilizing a type of bindingOnce mechanism to determine whether or not an attribute should be added based on its value.

It's important to keep these attributes within the template of the directive/component for this method to work effectively.

Note: AngularJS will only create watches for variables that are displayed in the user interface.

Best of luck with implementing this technique - I hope it proves to be beneficial for your project.

Angular Elements - Additional Attribute Bindings

(EDIT) Some Insights after conducting tests and research

Answer №1

Example Output

Potential Limitations

Considerations for Minification

Answer №2

Answer №3

Answer №4

Answer №5

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