Modal Components Skill

CRITICAL: All modals MUST use the global Modal component with the correct API

Overview

The Diddit! app has a centralized, reusable Modal component at apps/frontend/src/app/components/modals/modal/modal.ts. This component handles ALL modal functionality in one place:

• •✅ Backdrop click to close
• •✅ ESC key to close
• •✅ Close button (X) to close
• •✅ Focus trap
• •✅ Body scroll prevention
• •✅ Accessibility (ARIA attributes, roles)
• •✅ Animations

NEVER reimplement these features. ALWAYS use the global Modal component.

Correct API

Inputs

open = input<boolean>(false); // Whether modal is open
title = input<string>(''); // Modal title text
closeOnBackdropClick = input<boolean>(true); // Allow backdrop close (default: true)
closeOnEsc = input<boolean>(true); // Allow ESC close (default: true)

Outputs

closeModal = output<void>(); // Emitted when modal should close

CRITICAL: The output is closeModal, NOT closeRequested, NOT close, NOT anything else.

Template Pattern

✅ CORRECT Usage

<app-modal [open]="open()" (closeModal)="handleClose()" title="Modal Title">
  <!-- Your modal content here -->
  <form>
    <!-- Form fields -->
  </form>

  <!-- Action buttons (optional) -->
  <div class="modal-actions" modal-actions>
    <button type="button" class="btn btn-secondary" (click)="onCancel()">Cancel</button>
    <button type="submit" class="btn btn-primary">Submit</button>
  </div>
</app-modal>

Key Points

1. •Use [open] input - Pass a signal or boolean to control visibility
2. •Use (closeModal) output - Listen to the EXACT event name closeModal
3. •Use title input - Pass title as input property, NOT using slots
4. •Use modal-actions attribute - For footer buttons (optional)
5. •Content goes in default slot - Just put content inside <app-modal> tags

❌ WRONG - Do NOT Do This

<!-- WRONG: Using wrong event name -->
<app-modal [open]="open()" (closeRequested)="handleClose()">
  <!-- WRONG: Using slots for title -->
  <app-modal [open]="open()" (closeModal)="handleClose()">
    <h2 slot="title">Modal Title</h2>

    <!-- WRONG: Using old @Output name -->
    <app-modal [open]="open()" (close)="handleClose()">
      <!-- WRONG: Not binding to signal/property -->
      <app-modal open="true" (closeModal)="handleClose()"></app-modal></app-modal></app-modal
></app-modal>

Component TypeScript Pattern

✅ CORRECT Component

import { Component, input, output, signal } from '@angular/core';
import { Modal } from '../modals/modal/modal';

@Component({
  selector: 'app-my-modal',
  imports: [Modal],
  templateUrl: './my-modal.html',
  styleUrl: './my-modal.css',
})
export class MyModal {
  // Inputs
  open = input<boolean>(false);
  someData = input<string>('');

  // Outputs
  closeRequested = output<void>(); // Emit to parent when modal should close

  // Internal state
  submitting = signal(false);

  /**
   * Handle modal close (called by Modal's closeModal event)
   */
  handleClose(): void {
    this.closeRequested.emit();
  }

  /**
   * Handle cancel button
   */
  onCancel(): void {
    this.closeRequested.emit();
  }

  /**
   * Handle form submission
   */
  onSubmit(): void {
    // Do work...
    this.closeRequested.emit();
  }
}

Key Points

1. •Import Modal component - Add to imports array
2. •Accept open input - Let parent control visibility
3. •Emit closeRequested output - Let parent handle closing
4. •Create handleClose() method - Connect Modal's (closeModal) to your closeRequested output
5. •Don't manage open state internally - Parent controls it

Real Working Examples

Study these working modals in the codebase:

add-child-modal

• •Location: apps/frontend/src/app/components/modals/add-child-modal/
• •Pattern: Form modal with validation
• •Template: Uses (closeModal), title input, modal-actions slot

invite-modal

• •Location: apps/frontend/src/app/components/modals/invite-modal/
• •Pattern: Form modal with role selection
• •Template: Uses (closeModal), title input, modal-actions slot

task-form-modal

• •Location: apps/frontend/src/app/components/modals/task-form-modal/
• •Pattern: Complex form with conditional fields, delete confirmation
• •Template: Uses (closeModal), dynamic [title], modal-actions slot

Common Mistakes

❌ Mistake 1: Wrong Event Name

Problem: Listening for (closeRequested) or (close) instead of (closeModal)

<!-- WRONG -->
<app-modal [open]="open()" (closeRequested)="handleClose()"></app-modal>

Result: Modal won't close when clicking X, backdrop, or pressing ESC

Fix: Use (closeModal)

<!-- CORRECT -->
<app-modal [open]="open()" (closeModal)="handleClose()"></app-modal>

❌ Mistake 2: Using Slots for Title

Problem: Trying to use slot-based API that doesn't exist

<!-- WRONG -->
<app-modal [open]="open()" (closeModal)="handleClose()"> <h2 slot="title">My Title</h2></app-modal>

Result: Title appears in modal body, not header. Empty header shows.

Fix: Use title input

<!-- CORRECT -->
<app-modal [open]="open()" (closeModal)="handleClose()" title="My Title"></app-modal>

❌ Mistake 3: Duplicate Headers

Problem: Setting title on Modal AND adding header in content

<!-- WRONG -->
<app-modal [open]="open()" (closeModal)="handleClose()" title="Add Task">
  <h2>Add Task</h2>
  <!-- Duplicate header! -->
  <form>...</form>
</app-modal>

Result: Two headers appear

Fix: Only use Modal's title input

<!-- CORRECT -->
<app-modal [open]="open()" (closeModal)="handleClose()" title="Add Task">
  <form>...</form>
  <!-- No duplicate header -->
</app-modal>

Storybook Requirement

CRITICAL: Every modal component MUST have a Storybook story.

Why?

Storybook catches modal bugs immediately:

• •Close functionality (X button, backdrop, ESC)
• •Header rendering
• •Form validation
• •Loading states
• •Error states

Story Template

// my-modal.stories.ts
import type { Meta, StoryObj } from '@storybook/angular';
import { MyModal } from './my-modal';

const meta: Meta<MyModal> = {
  title: 'Components/Modals/MyModal',
  component: MyModal,
  tags: ['autodocs'],
  argTypes: {
    open: { control: 'boolean' },
  },
};

export default meta;
type Story = StoryObj<MyModal>;

export const Default: Story = {
  args: {
    open: true,
  },
};

export const Closed: Story = {
  args: {
    open: false,
  },
};

export const WithData: Story = {
  args: {
    open: true,
    someData: 'Example data',
  },
};

Testing Checklist in Storybook

When viewing your modal story, verify:

• • Modal opens when open: true
• • Modal closes when clicking X button
• • Modal closes when clicking backdrop
• • Modal closes when pressing ESC key
• • Modal title appears in header (not body)
• • Only ONE header appears (no duplicates)
• • Form validation works
• • Action buttons work
• • Loading states work
• • Error states work

Modal Component Source

For reference, the global Modal component is at:

TypeScript: apps/frontend/src/app/components/modals/modal/modal.ts

• •Inputs: open, title, closeOnBackdropClick, closeOnEsc
• •Outputs: closeModal
• •Methods: onBackdropClick(), onEscapeKey(), onCloseClick(), onTabKey()

Template: apps/frontend/src/app/components/modals/modal/modal.html

• •Overlay with backdrop click handler
• •Header with title and close button
• •Body with <ng-content> for default content
• •Footer with <ng-content select="[modal-actions]"> for action buttons

Styles: apps/frontend/src/app/components/modals/modal/modal.css

• •Animations, layout, accessibility

Quick Checklist

Before creating a modal, verify:

• • Import Modal component
• • Use (closeModal) output (NOT closeRequested, NOT close)
• • Use title input (NOT slots)
• • Accept open input from parent
• • Emit closeRequested to parent
• • Create handleClose() method to bridge events
• • Use modal-actions attribute for footer buttons
• • Create Storybook story
• • Test all close methods in Storybook (X, backdrop, ESC)
• • Verify no duplicate headers

Summary

The golden rule: Study existing working modals (add-child-modal, invite-modal, task-form-modal) and copy their patterns exactly. Don't invent new APIs or patterns.