Category: Storybook

 207 total views

Previously, I created a story book for simple component with inputs only (link) . In this post, I want to add new stories for a simple components with both input and action.

The component is FoodChoiceComponent that has two states: choice available to order and choice that has sold out.

If choice is available, user can input quantity and submit the reactive form. Otherwise, the component hides the form and displays a message, “Sorry, this choice is sold out”.

Create a food choice component in food module

ng g c foodChoice --module=food

Food choice component is a simple presentational component that is consisted of name, description, price, quantity and a reactive form.

// food-choice.component.ts 

// for the sakes of brevity, import statements are omitted

@Component({
  selector: 'app-food-choice',
  templateUrl: './food-choice.component.html',
  styleUrls: ['./food-choice.component.scss'],
  changeDetection: ChangeDetectionStrategy.OnPush,
})
export class FoodChoiceComponent implements OnInit, OnDestroy {
  @Input()
  choice: Choice

  @Output()
  foodChoiceAdded = new EventEmitter<OrderedFoodChoice>()

  submitChoice$ = new Subject<Event>()
  unsubscribe$ = new Subject<boolean>()
  processing = false

  form = this.fb.group({
    quantity: new FormControl(1, [Validators.required, Validators.min(1)]),
  })

  constructor(private fb: FormBuilder) {}

  ngOnInit(): void {
    this.submitChoice$
      .pipe(
        tap(($event) => {
          $event.preventDefault()
          $event.stopPropagation()
          this.processing = true
        }),
        delay(1000),
        map(() => ({
          ...this.form.value,
          name: this.choice.name,
          description: this.choice.description,
          price: this.choice.price,
        })),
        tap(() => (this.processing = false)),
        takeUntil(this.unsubscribe$),
      )
      .subscribe((value) => this.foodChoiceAdded.emit(value))
  }

  get quantity() {
    return this.form.get('quantity') as FormControl
  }

  ngOnDestroy(): void {
    this.unsubscribe$.next(true)
    this.unsubscribe$.complete()
  }
}

// food-choice.component.html

<div class="container">
  ...
  <ng-container [ngSwitch]="choice.available">
    <form [formGroup]="form" (ngSubmit)="submitChoice$.next($event)" *ngSwitchCase="true">
      <label name="quantity" class="item">
        <span class="field">Quantity: </span>
        <input type="number" formControlName="quantity" />
      </label>
      <div *ngIf="quantity.invalid && (quantity.touched || quantity.dirty)" class="alert alert-danger">
        <div *ngIf="quantity.errors?.min" class="error">Quantity must be at least {{ quantity.errors?.min?.min }}.</div>
      </div>
      <div *ngIf="processing" class="alert">
        <div class="processing">Loading...</div>
      </div>
      <button type="submit" [disabled]="processing || form.value.quantity <= 0">Submit</button>
    </form>
    <ng-container *ngSwitchDefault>
      <ng-container *ngTemplateOutlet="soldout; context: { choice: choice }"> </ng-container>
    </ng-container>
  </ng-container>
  <ng-template #soldout let-choice="choice">
    <span class="item sold-out">Sorry, {{ choice.name }} is sold out</span>
  </ng-template>
</div>

Input is a Choice interface that has several properties

export interface Choice {
  id: string
  name: string
  description: string
  price: number
  available: boolean
}

The food choice component has an event emitter that emits the user’s choice to container component. When user submits the reactive form, the submit event notifies RxJS subject to process the data and to emit the result to container component.

<form [formGroup]="form" (ngSubmit)="submitChoice$.next($event)" *ngIf="choice.available; else soldout">
....
</form>

submitChoice$ = new Subject<Event>()

@Output()
foodChoiceAdded = new EventEmitter<OrderedFoodChoice>()

form = this.fb.group({
  quantity: new FormControl(1, [Validators.required, Validators.min(1)]),
})

ngOnInit(): void {
    this.submitChoice$
      .pipe(
        tap(($event) => {
          $event.preventDefault()
          $event.stopPropagation()
          this.processing = true
        }),
        delay(1000),
        map(() => ({
          ...this.form.value,
          name: this.choice.name,
          description: this.choice.description,
          price: this.choice.price,
        })),
        tap(() => (this.processing = false)),
        takeUntil(this.unsubscribe$),
      )
      .subscribe((value) => this.foodChoiceAdded.emit(value))
}

Create Storybook for Food Choice Component

Create food-choice.stories.ts under the food folder

// food-choice.storeis.ts
import { moduleMetadata } from '@storybook/angular'
// also exported from '@storybook/angular' if you can deal with breaking changes in 6.1
import { Story, Meta } from '@storybook/angular/types-6-0'
import { FoodChoiceComponent } from '@/food'
import { FormsModule, ReactiveFormsModule } from '@angular/forms'

export default {
  title: 'Food Choice',
  component: FoodChoiceComponent,
  decorators: [
    moduleMetadata({
      imports: [ReactiveFormsModule, FormsModule],
    }),
  ],
  argTypes: { onClick: { action: 'clicked' } },
} as Meta

const Template: Story<FoodChoiceComponent> = (args: FoodChoiceComponent) => ({
  props: args,
})

export const Primary = Template.bind({})
Primary.args = {
  choice: {
    id: '1',
    name: 'Vino tinto',
    description: 'Red wine',
    price: 12.99,
    available: true,
  },
}

export const Soldout = Template.bind({})
Soldout.args = {
  choice: {
    id: '1',
    name: 'Vino tinto',
    description: 'Red wine',
    price: 12.99,
    available: false,
  },
}

Two stories are created for FoodChoiceComponent, Primary and Soldout. Primary renders that state of an available food choice while Soldout renders the state of a sold out food choice.

Start storybook application

npm run storybook

Click the title Food Choice -> Primary and the component is rendered with reactive form

When quantity is updated and submitted, event is emitted and logged on Actions tab

Click the title Food Choice -> Soldout and the component is rendered with a sold out message.

This is the end of the blog post and we will keep you posted after progress is made, thanks.

Resources:

1. Repo: https://github.com/railsstudent/ng-spanish-menu
2. Storybook: Build a simple component: https://storybook.js.org/tutorials/intro-to-storybook/angular/en/simple-component/
3. Actions: https://storybook.js.org/docs/angular/essentials/actions

 218 total views

I recently completed Visual DOM course at Angular Nation and the course covers advanced materials and is beneficial to Angular developers of any level. I personally struggle with the concept of view container ref (vcr) and would like to build a side project about it with my mentor, Nati.

The idea of the application is to displays a restaurant menu in Spanish (I am also learning Spanish), user can order food and beverages from the menu and the selection is added to the page dynamically through vcr. The project is at the early stage and we use storybook to visualize the components as the application comes along the way.

Create an angular application

ng new ng-spanish-menu

Install storybook dependencies

# Add Storybook:
npx sb init

The command adds storybook script in package.json and developer can run npm run storybook to launch storybook site at http://localhost:6006.

Create a food module

ng g module food

This module keeps food-related components and services.

Create a food card component in food module

ng g c foodCard --module=food

Food card component is a simple presentational component that displays name, description, price, quantity and total amount of a food/beverage.

// food-card.component.ts 

import { ChangeDetectionStrategy, Component, Input } from '@angular/core'

@Component({
  selector: 'app-food-card',
  templateUrl: './food-card.component.html',
  styleUrls: ['./food-card.component.scss'],
  changeDetection: ChangeDetectionStrategy.OnPush,
})
export class FoodCardComponent {
  @Input()
  name: string

  @Input()
  description: string

  @Input()
  price: number

  @Input()
  quantity: number

  get total() {
    return Math.round(this.price * this.quantity * 100) / 100
  }
}

// food-card.component.html

<div class="container">
  <label name="name" class="item">
    <span class="field">Name:</span>
    <span>{{ name }}</span>
  </label>
  <label class="item" name="description">
    <span class="field">Description:</span>
    <span>{{ description }}</span>
  </label>
  <label class="item" name="price">
    <span class="field">Price:</span>
    <span>{{ price }}</span>
  </label>
  <label class="item" name="quantity">
    <span class="field">Quantity:</span>
    <span>{{ quantity }}</span>
  </label>
  <label class="item" name="total">
    <span class="field">Total:</span>
    <span>USD {{ total }}</span>
  </label>
</div>

Create Storybook for Food Card Component

Create a new food folder under stories.

Create food-card.stories.ts under the food folder

// food-card.storeis.ts
// also exported from '@storybook/angular' if you can deal with breaking changes in 6.1
import { Story, Meta } from '@storybook/angular/types-6-0'
import { FoodCardComponent } from '@/food'

export default {
  title: 'Food Card',
  component: FoodCardComponent,
} as Meta

const Template: Story<FoodCardComponent> = (args: FoodCardComponent) => ({
  props: args,
})

export const Primary = Template.bind({})
Primary.args = {
  name: 'Vino tinto',
  description: 'Red wine',
  price: 12.99,
  quantity: 3,
}

Then, input values are supplied to Primary.args and subsequently passed to FoodCardComponent to be displayed.

Start storybook application

npm run storybook

Click the title Food Card -> Primary and the component is rendered with initial input values.

Input values can be updated and then the component re-renders with new values.

CSS is very simple currently but Nati and I can work on the styling later after functionality is completed.

I am very excited of this project because Nati is very talented Angular developer and we can learn from each other while we work it together and she teaches me Spanish.

This is the end of the blog post and we will keep you posted after progress is made, thanks.

Resources:

1. Repo: https://github.com/railsstudent/ng-spanish-menu
2. Install Storybook: https://storybook.js.org/docs/react/get-started/install
3. Storybook: Build a simple component: https://storybook.js.org/tutorials/intro-to-storybook/angular/en/simple-component/