Manipulating every component of a page in one go with Angular 2 (including third-party and custom components)

Question

Manipulating every component of a page in one go with Angular 2 (including third-party and custom components)

I previously inquired about a solution on Another Question. However, I wanted to get further clarification here and explore if there is a more streamlined approach to achieve the desired effect depicted in the image below.

In case where multiple components are present on a page (some of them possibly containing child components), I am aiming to add a border around each one (potentially with randomly changing colors) and display the component name (or selector name) at the upper right corner of each component's box. My goal is to easily identify the layout of components on the page.

There are 2 key questions I have:

1. What would be the simplest method to accomplish this when there are both custom and third-party components on the page?

2. How can this be achieved most easily for custom components only?

Please note: I prefer a non-intrusive way to implement this feature and it should be possible to show/hide the borders and component names using a global variable that can be toggled for debugging purposes.

This is the desired outcome I aim to achieve: https://i.sstatic.net/gUlIe.jpg

Update: I have added 2 screenshots

Application components: https://i.sstatic.net/02uTA.jpg

Batarangle 2 view of the application: https://i.sstatic.net/fdMVQ.jpg

typescript angular

Answer 1

Answer №1

Here's my approach, where I simply added a border. If there's a more concise solution out there, please share it with me.

I've developed a directive that applies a border style to any component extended with the "componentcolor" directive. By default, the color is set to blue but can be customized during directive declaration.

For components with child components, they need to include: directives: [ComponentVisualizerDirective]

This method may seem intrusive compared to my previous solution involving inheriting a base component class.

componentvisualizer.ts

import {Directive,ElementRef,OnInit} from 'angular2/core';

@Directive({
    selector:'[componentcolor]',
    properties: [
        'color: componentcolor'
    ]
})
export class ComponentVisualizerDirective implements OnInit
{
    private color: string = 'blue';
    constructor(private _el:ElementRef) {
    }

    ngOnInit():void {
        this._el.nativeElement.style.border = '1px solid ' + this.color;
        this._el.nativeElement.style.display = 'block';
    }

}

application.html

<auction-navbar component></auction-navbar>

<div class="container">
    <div class="row">
        <!-- Left column contains only search form the style col-md-3 comes from
        Twitter Bootstrap grid system-->
        <div class="col-md-3">
            <auction-search component="green"></auction-search>
        </div>
    </div>
</div>

application.ts

import {Component} from 'angular2/core';
import NavbarComponent from "../navbar/navbar";
import SearchComponent from "../search/search";
import {ComponentVisualizerDirective} from "../../directives/componentvisualizer";

@Component({
    selector: 'auction-application',
    templateUrl: 'app/components/application/application.html',
    directives: [
        NavbarComponent,
        SearchComponent,
        ComponentVisualizerDirective]
})
export default class ApplicationComponent {
}

Answer 2

Here's my approach, where I simply added a border. If there's a more concise solution out there, please share it with me.

I've developed a directive that applies a border style to any component extended with the "componentcolor" directive. By default, the color is set to blue but can be customized during directive declaration.

For components with child components, they need to include: directives: [ComponentVisualizerDirective]

This method may seem intrusive compared to my previous solution involving inheriting a base component class.

componentvisualizer.ts

import {Directive,ElementRef,OnInit} from 'angular2/core';

@Directive({
    selector:'[componentcolor]',
    properties: [
        'color: componentcolor'
    ]
})
export class ComponentVisualizerDirective implements OnInit
{
    private color: string = 'blue';
    constructor(private _el:ElementRef) {
    }

    ngOnInit():void {
        this._el.nativeElement.style.border = '1px solid ' + this.color;
        this._el.nativeElement.style.display = 'block';
    }

}

application.html

<auction-navbar component></auction-navbar>

<div class="container">
    <div class="row">
        <!-- Left column contains only search form the style col-md-3 comes from
        Twitter Bootstrap grid system-->
        <div class="col-md-3">
            <auction-search component="green"></auction-search>
        </div>
    </div>
</div>

application.ts

import {Component} from 'angular2/core';
import NavbarComponent from "../navbar/navbar";
import SearchComponent from "../search/search";
import {ComponentVisualizerDirective} from "../../directives/componentvisualizer";

@Component({
    selector: 'auction-application',
    templateUrl: 'app/components/application/application.html',
    directives: [
        NavbarComponent,
        SearchComponent,
        ComponentVisualizerDirective]
})
export default class ApplicationComponent {
}

Answer 3

Answer №2

An alternative method would involve searching for elements that have an attribute beginning with _nghost.

While this approach may not be as elegant as using directives, it can handle cases where components are indirectly used in the code, such as third-party components importing others.

I created a service that allows you to access all component elements present in the document body.

import {Injectable} from 'angular2/core';

@Injectable()
export class ComponentDecorationService {

    public forAllComponents(action: (e: HTMLElement) => void) {

        this.highlight(document.body, action);
    }

    private highlight(element: HTMLElement | Element, action: (e: Element) => void) {

        if (element.attributes) {
            for (var j = 0; j < element.attributes.length; j++) {
                if (element.attributes.item(j).name.startsWith("_nghost")) {
                    action(element);
                }
            }
        }

        if (element instanceof HTMLElement && element.children) {
            for (var i = 0; i < element.children.length; i++) {
                this.highlight(element.children[i], action);
            }
        }

    }
}

To use this service:

export class App {

  constructor(private ComponentDecorationService: ComponentDecorationService) {}

  ngAfterViewInit() {

    this.ComponentDecorationService.forAllComponents((e) => {
      e.classList.add('highlighted-component');
    })
  }

}

Answer 4

An alternative method would involve searching for elements that have an attribute beginning with _nghost.

While this approach may not be as elegant as using directives, it can handle cases where components are indirectly used in the code, such as third-party components importing others.

I created a service that allows you to access all component elements present in the document body.

import {Injectable} from 'angular2/core';

@Injectable()
export class ComponentDecorationService {

    public forAllComponents(action: (e: HTMLElement) => void) {

        this.highlight(document.body, action);
    }

    private highlight(element: HTMLElement | Element, action: (e: Element) => void) {

        if (element.attributes) {
            for (var j = 0; j < element.attributes.length; j++) {
                if (element.attributes.item(j).name.startsWith("_nghost")) {
                    action(element);
                }
            }
        }

        if (element instanceof HTMLElement && element.children) {
            for (var i = 0; i < element.children.length; i++) {
                this.highlight(element.children[i], action);
            }
        }

    }
}

To use this service:

export class App {

  constructor(private ComponentDecorationService: ComponentDecorationService) {}

  ngAfterViewInit() {

    this.ComponentDecorationService.forAllComponents((e) => {
      e.classList.add('highlighted-component');
    })
  }

}

Answer 5

Answer №3

If you want to customize a component's behavior, one approach is to highjack it using monkey patching techniques as explained in this helpful article: . By modifying the @Component directive, you can tailor the component's functionality to suit your specific needs.

Answer 6

If you want to customize a component's behavior, one approach is to highjack it using monkey patching techniques as explained in this helpful article: . By modifying the @Component directive, you can tailor the component's functionality to suit your specific needs.

Answer 7

Answer №4

Take a look at my response to toskv@ answer. I came up with this solution. Once the Show() method is executed below, the bellowcomponentsanddirectives array will be populated as follows:

["auction-application", "auction-carousel", "auction-footer", "auction-navbar", "auction-product-item", "auction-stars", "[component]", "auction-search", "[component]"]

Note: [component] represents the selector for a custom directive. One issue I couldn't resolve (filtering out directives) is: the annotation variable can either be of type ComponentMetadata or DirectiveMetadata. The typeof annotation returns "object" even though I see the correct type in Chrome Js console when entering: annotation.

export default class ApplicationComponent {
    componentsanddirectives: string[] = [];
    constructor(private _applicationRef: ApplicationRef) {}

    Show():void {
        let config = {};
        // a hack to get app element in shadow dom
        let appElement: ElementRef = this._applicationRef['_rootComponents'][0].location;


        this._applicationRef.componentTypes.forEach((component) => {
            let annotations = reflector.annotations(component);
            this.RecursiveCall(config, annotations);
        });
    }

    RecursiveCall(config:  {}, annotations: any )
    {
        annotations.forEach((annotation) => {
            this.componentsanddirectives.push(annotation.selector);
        });

        if (annotations[0].directives != undefined && annotations[0].directives.length > 0)
        {
            annotations[0].directives.forEach((component) => {
                let annotations = reflector.annotations(component);
                this.RecursiveCall(config, annotations);
            });

        }
    }
}

This image showcases the content of the annotation variable during recursion: https://i.sstatic.net/YlAEt.jpg

Answer 8

Take a look at my response to toskv@ answer. I came up with this solution. Once the Show() method is executed below, the bellowcomponentsanddirectives array will be populated as follows:

["auction-application", "auction-carousel", "auction-footer", "auction-navbar", "auction-product-item", "auction-stars", "[component]", "auction-search", "[component]"]

Note: [component] represents the selector for a custom directive. One issue I couldn't resolve (filtering out directives) is: the annotation variable can either be of type ComponentMetadata or DirectiveMetadata. The typeof annotation returns "object" even though I see the correct type in Chrome Js console when entering: annotation.

export default class ApplicationComponent {
    componentsanddirectives: string[] = [];
    constructor(private _applicationRef: ApplicationRef) {}

    Show():void {
        let config = {};
        // a hack to get app element in shadow dom
        let appElement: ElementRef = this._applicationRef['_rootComponents'][0].location;


        this._applicationRef.componentTypes.forEach((component) => {
            let annotations = reflector.annotations(component);
            this.RecursiveCall(config, annotations);
        });
    }

    RecursiveCall(config:  {}, annotations: any )
    {
        annotations.forEach((annotation) => {
            this.componentsanddirectives.push(annotation.selector);
        });

        if (annotations[0].directives != undefined && annotations[0].directives.length > 0)
        {
            annotations[0].directives.forEach((component) => {
                let annotations = reflector.annotations(component);
                this.RecursiveCall(config, annotations);
            });

        }
    }
}

This image showcases the content of the annotation variable during recursion: https://i.sstatic.net/YlAEt.jpg

Manipulating every component of a page in one go with Angular 2 (including third-party and custom components)

Answer №1

Answer №2

Answer №3

Answer №4

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