Using Angular and Typescript: Enter a string in a component class

Question

Using Angular and Typescript: Enter a string in a component class

I am facing an issue where a function is passing the name of my component as a string, but I actually need it to be the actual component class:

Currently: "MyComponent" Required: MyComponent

I need to find a way to properly convert it. In my code, there is an ngFor loop that iterates over values from a dashboard array, and I am attempting to use a pipe to handle this conversion:

<div id="grid">
    <gridster [options]="options">
    <gridster-item [item]="item" *ngFor="let item of dashboard; let i = index;">
      <div class="grid-header drag-handle">
        <span class="handle-icon"><i class="material-icons">open_with</i></span>
        <span class="close-icon" (click)="removePanel(item)"><i class="material-icons">close</i></span>
      </div>
      <div class="grid-content">
        <ndc-dynamic [ndcDynamicComponent]="item.viewType | dynamicComponent"></ndc-dynamic>
      </div>
    </gridster-item>
  </gridster>
</div>

In the code snippet above, you can see that I have a property called item.viewType which is a string coming from my item array. I am passing this value to a custom pipe called dynamicComponent. I have imported all my components into my dynamic-component.pipe.ts file. The challenge is to transform the string into the specified viewType and return the typed value:

import { Pipe, PipeTransform } from '@angular/core';
// Importing all possible components
import * from '../../views';

@Pipe({
  name: 'dynamicComponent'
})
export class DynamicComponentPipe implements PipeTransform {

  transform(value: string): any {
     

  }

}

javascript angular typescript

Answer 1

Answer №1

To establish a connection between string values and components, you must create a mapping manually. Components function as named entities that can be condensed into shorter variable names during production compilation.

import ComponentA from '../views/ComponentA'; 
import ComponentB from '../views/ComponentA';

const componentMap = {
    'ComponentA': ComponentA,
    'ComponentB': ComponentB
};

@Pipe({name: 'dynamicComponent'})
export class DynamicComponentPipe implements PipeTransform {
   transform(value: string): any {
       if(componentMap[value]) {
          return componentMap[value];
       }
       throw new Error(`${componentMap} component was not found`);
   }
}

UPDATED:

The challenge with using the component name at runtime is that it could be transformed into a shorter variable name for production purposes. Hence, utilizing something like views['MyComponent'] may fail later when MyComponent is renamed to something like a12.

An alternative method involves employing the component's selector string value for selection. Each Angular component must have a unique selector string, making it a reliable identifier.

In Angular 5, you can access the component's metadata through the __annotations__ property, which contains an array of metadata.

One possible solution is:

import * as views from '../views';

@Pipe({name: 'dynamicComponent'})
export class DynamicComponentPipe implements PipeTransform {
   transform(value: string): any {
       const view = views.filter((component)=>component['__annotations__'][0]['selector'] === value));
       if(view) {
          return view;
       }
       throw new Error(`A component with selector "${value}" was not found`);
   }
}

Moreover, you can eliminate the necessity for a views file by directly accessing the ngModule and iterating over all components to locate a matching selector. Modules possess the same __annotations__ property.

Answer 2

To establish a connection between string values and components, you must create a mapping manually. Components function as named entities that can be condensed into shorter variable names during production compilation.

import ComponentA from '../views/ComponentA'; 
import ComponentB from '../views/ComponentA';

const componentMap = {
    'ComponentA': ComponentA,
    'ComponentB': ComponentB
};

@Pipe({name: 'dynamicComponent'})
export class DynamicComponentPipe implements PipeTransform {
   transform(value: string): any {
       if(componentMap[value]) {
          return componentMap[value];
       }
       throw new Error(`${componentMap} component was not found`);
   }
}

UPDATED:

The challenge with using the component name at runtime is that it could be transformed into a shorter variable name for production purposes. Hence, utilizing something like views['MyComponent'] may fail later when MyComponent is renamed to something like a12.

An alternative method involves employing the component's selector string value for selection. Each Angular component must have a unique selector string, making it a reliable identifier.

In Angular 5, you can access the component's metadata through the __annotations__ property, which contains an array of metadata.

One possible solution is:

import * as views from '../views';

@Pipe({name: 'dynamicComponent'})
export class DynamicComponentPipe implements PipeTransform {
   transform(value: string): any {
       const view = views.filter((component)=>component['__annotations__'][0]['selector'] === value));
       if(view) {
          return view;
       }
       throw new Error(`A component with selector "${value}" was not found`);
   }
}

Moreover, you can eliminate the necessity for a views file by directly accessing the ngModule and iterating over all components to locate a matching selector. Modules possess the same __annotations__ property.

Answer 3

Answer №2

Here's how I approached this task:

To streamline my workflow, I organized all my views in a file called views.ts located at the root of my views directory. Next, in the directory where my pipe is utilized, I imported the views like so:

import * as views from '../../views/views'

Within my transform method, I simply used return views[value]; where value represents the string retrieved from the template.

Answer 4

Here's how I approached this task:

To streamline my workflow, I organized all my views in a file called views.ts located at the root of my views directory. Next, in the directory where my pipe is utilized, I imported the views like so:

import * as views from '../../views/views'

Within my transform method, I simply used return views[value]; where value represents the string retrieved from the template.

Using Angular and Typescript: Enter a string in a component class

Answer №1

Answer №2

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