Transform input into an encapsulated class

Question

Transform input into an encapsulated class

In order to convert the http response interface to the view model in my component, I have created an inner class to hold the necessary data. Here is my attempt:

@Component({
  selector: 'app-tasklist-items-grid',
  templateUrl: './tasklist-items-grid.component.html',
  styleUrls: ['./tasklist-items-grid.component.scss'],
  providers: [TasklistItemsService, BsModalService]
})
export class TasklistItemsGridComponent implements OnInit {

// .....

  TaskListItemViewModel = class {    
    id?: number;
    tasklistId: number;
    typeOfTask: number;
    statusId: number;
    created_at: Date;
    updated_at: Date;
    checked: Boolean;
    rowVersion: number;
  }

  convertToViewModel = (item: TaskListItemViewModel) => item;
}

However, the 'TaskListItemViewModel' type is not being found. I have tried to define both the inner class and the method as static, but it still does not work.

What could I be missing here?

angular typescript

Answer 1

Answer №1

In order to organize your code, you can define an interface for your model outside of the component. Within the component, you can then create a nested class using a class expression that implements this interface. You can also define additional methods within this nested class.

import { Component } from '@angular/core';

export interface MyInterface {
  id?: number;
  tasklistId: number;
  typeOfTask: number;
  // other properties
}
@Component({
  selector: 'my-app',
  templateUrl: './app.component.html',
  styleUrls: [ './app.component.css' ]
})
export class AppComponent  {
  TaskListItemViewModel = class implements MyInterface {
    constructor(
      public id: number,
      public tasklistId: number,
      public typeOfTask: number
    ) {}
    // other methods that you want to include
  }

  convertToViewModel = (item: MyInterface) => new this.TaskListItemViewModel(1, 2, 3);
}

While this example demonstrates the versatility of TypeScript with features like Class expressions, it is not recommended for real projects. It is advisable to follow popular style guides that suggest declaring classes, interfaces, and enums (models) in separate files like some-feature.model.ts. This approach allows for better organization and reusability of models throughout the application.

Answer 2

In order to organize your code, you can define an interface for your model outside of the component. Within the component, you can then create a nested class using a class expression that implements this interface. You can also define additional methods within this nested class.

import { Component } from '@angular/core';

export interface MyInterface {
  id?: number;
  tasklistId: number;
  typeOfTask: number;
  // other properties
}
@Component({
  selector: 'my-app',
  templateUrl: './app.component.html',
  styleUrls: [ './app.component.css' ]
})
export class AppComponent  {
  TaskListItemViewModel = class implements MyInterface {
    constructor(
      public id: number,
      public tasklistId: number,
      public typeOfTask: number
    ) {}
    // other methods that you want to include
  }

  convertToViewModel = (item: MyInterface) => new this.TaskListItemViewModel(1, 2, 3);
}

While this example demonstrates the versatility of TypeScript with features like Class expressions, it is not recommended for real projects. It is advisable to follow popular style guides that suggest declaring classes, interfaces, and enums (models) in separate files like some-feature.model.ts. This approach allows for better organization and reusability of models throughout the application.

Answer 3

Answer №2

To define a class outside of TasklistItemsGridComponent, use the syntax below. If you need to create nested classes, refer to the solutions provided in this Stack Overflow post:

class TaskListItemViewModel { 
  id?: number;
  tasklistId: number;
  typeOfTask: number;
  statusId: number;
  created_at: Date;
  updated_at: Date;
  checked: Boolean;
  rowVersion: number;
}

@Component({
  selector: 'app-tasklist-items-grid',
  templateUrl: './tasklist-items-grid.component.html',
  styleUrls: ['./tasklist-items-grid.component.scss'],
  providers: [TasklistItemsService, BsModalService]
})
export class TasklistItemsGridComponent implements OnInit {
   convertToViewModel = (item: TaskListItemViewModel) => item;
}

Answer 4

To define a class outside of TasklistItemsGridComponent, use the syntax below. If you need to create nested classes, refer to the solutions provided in this Stack Overflow post:

class TaskListItemViewModel { 
  id?: number;
  tasklistId: number;
  typeOfTask: number;
  statusId: number;
  created_at: Date;
  updated_at: Date;
  checked: Boolean;
  rowVersion: number;
}

@Component({
  selector: 'app-tasklist-items-grid',
  templateUrl: './tasklist-items-grid.component.html',
  styleUrls: ['./tasklist-items-grid.component.scss'],
  providers: [TasklistItemsService, BsModalService]
})
export class TasklistItemsGridComponent implements OnInit {
   convertToViewModel = (item: TaskListItemViewModel) => item;
}

Answer 5

Answer №3

To meet your specifications, you can utilize it in the following manner:

@Component({
  selector: 'app-tasklist-items-grid',
  templateUrl: './tasklist-items-grid.component.html',
  styleUrls: ['./tasklist-items-grid.component.scss'],
  providers: [TasklistItemsService, BsModalService]
})
export class TasklistItemsGridComponent implements OnInit {
 taskListItem: TaskListItemViewModel;
 constructor() {
   // place it here or in ngOnInit
   // this.taskListItem = new TaskListItemViewModel();
 }
// .....
 ngOnInit() {
   // this.taskListItem = new TaskListItemViewModel();
 }
  convertToViewModel = (item: ITaskListItemViewModel) => item;
}

// in another file or within the same component, you can define this class
export class TaskListItemViewModel implements ITaskListItemViewModel{    
    id?: number;
    tasklistId: number;
    typeOfTask: number;
    statusId: number;
    created_at: Date;
    updated_at: Date;
    checked: Boolean;
    rowVersion: number;
  }

interface ITaskListItemViewModel{    
        id: number;
        tasklistId: number;
        typeOfTask: number;
        statusId: number;
        created_at: Date;
        updated_at: Date;
        checked: Boolean;
        rowVersion: number;
      }

Answer 6

To meet your specifications, you can utilize it in the following manner:

@Component({
  selector: 'app-tasklist-items-grid',
  templateUrl: './tasklist-items-grid.component.html',
  styleUrls: ['./tasklist-items-grid.component.scss'],
  providers: [TasklistItemsService, BsModalService]
})
export class TasklistItemsGridComponent implements OnInit {
 taskListItem: TaskListItemViewModel;
 constructor() {
   // place it here or in ngOnInit
   // this.taskListItem = new TaskListItemViewModel();
 }
// .....
 ngOnInit() {
   // this.taskListItem = new TaskListItemViewModel();
 }
  convertToViewModel = (item: ITaskListItemViewModel) => item;
}

// in another file or within the same component, you can define this class
export class TaskListItemViewModel implements ITaskListItemViewModel{    
    id?: number;
    tasklistId: number;
    typeOfTask: number;
    statusId: number;
    created_at: Date;
    updated_at: Date;
    checked: Boolean;
    rowVersion: number;
  }

interface ITaskListItemViewModel{    
        id: number;
        tasklistId: number;
        typeOfTask: number;
        statusId: number;
        created_at: Date;
        updated_at: Date;
        checked: Boolean;
        rowVersion: number;
      }

Transform input into an encapsulated class

Answer №1

Answer №2

Answer №3

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