Build an Angular Expandable and Collapsible Sidebar with Icons

Creating an expandable and collapsible sidebar in Angular can significantly enhance the user experience of your application. This tutorial provides a step-by-step guide to building such a sidebar, complete with icons and smooth transitions. We’ll cover everything from setting up the component structure to applying styles and logic for toggling the sidebar.

Why Use a Collapsible Sidebar?

A collapsible sidebar improves the usability of an application by:

• Saving screen space.
• Providing easy navigation.
• Keeping the interface clean and organized.

Step-by-Step Guide to Build the Sidebar

1. Set Up Your Angular Project

First, ensure you have Angular CLI installed. If not, run:

npm install -g @angular/cli

Create a new Angular project:

ng new angular-sidebar
cd angular-sidebar

Generate the necessary components:

ng generate component sidebar

2. Define the Sidebar Structure

app.component.html

This will serve as the main container for the application. Add the sidebar and a button for toggling its state:

<div>



<h4>
  
  
  <strong>app.component.ts</strong>
</h4>

<p>Add the logic to manage the sidebar's state:<br>
</p>

<pre class="brush:php;toolbar:false">import { Component } from '@angular/core';

@Component({
  selector: 'my-app',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.scss'],
})
export class AppComponent {
  isSidebarCollapsed = false;

  onSidebarToggle() {
    this.isSidebarCollapsed = !this.isSidebarCollapsed;
  }
}

3. Implement the Sidebar Component

sidebar.component.html

Define the sidebar's HTML structure, including a menu with nested items:

<div>



<h4>
  
  
  <strong>sidebar.component.ts</strong>
</h4>

<p>Handle the toggle logic for menu items and sidebar:<br>
</p>

<pre class="brush:php;toolbar:false">import { Component, EventEmitter, Input, Output } from '@angular/core';

interface MenuItem {
  icon: string;
  label: string;
  children?: MenuItem[];
  isOpen?: boolean;
}

@Component({
  selector: 'app-sidebar',
  templateUrl: './sidebar.component.html',
  styleUrls: ['./sidebar.component.scss'],
})
export class SidebarComponent {
  @Input() isSidebarCollapsed = false;
  @Output() sidebarToggle = new EventEmitter<void>();

  menuItems: MenuItem[] = [
    {
      icon: 'fas fa-home',
      label: 'Dashboard',
      isOpen: false,
      children: [
        { icon: 'fas fa-chart-pie', label: 'Analytics' },
        { icon: 'fas fa-tasks', label: 'Projects' },
      ]
    },
    {
      icon: 'fas fa-cog',
      label: 'Settings',
      isOpen: false,
      children: [
        { icon: 'fas fa-user', label: 'Profile' },
        { icon: 'fas fa-lock', label: 'Security' },
      ]
    },
    {
      icon: 'fas fa-envelope',
      label: 'Messages'
    }
  ];

  toggleSidebar() {
    this.sidebarToggle.emit();
  }

  toggleMenuItem(item: MenuItem) {
    // Only toggle if sidebar is not collapsed and item has children
    if (!this.isSidebarCollapsed && item.children) {
      item.isOpen = !item.isOpen;
    }
  }
}

4. Style the Sidebar

app.component.scss

Add global styles for layout and transitions:

.app-container {
  display: flex;
  height: 100vh;
  overflow: hidden;
}

.content {
  flex-grow: 1;
  margin-left: 250px;
  transition: all 0.3s ease-in-out;
  background-color: #f4f6f7;
  overflow-y: auto;

  &-inner {
    padding: 2rem;
    max-width: 1200px;
    margin: 0 auto;
  }

  &-expanded {
    margin-left: 50px;
  }
}

.sidebar-toggle-btn {
  position: absolute;
  top: 1rem;
  left: 200px; // Default position when sidebar is expanded
  background-color: #2c3e50;
  border: none;
  color: #fff;
  padding: 0.5rem;
  border-top-right-radius: 0.5rem;
  border-bottom-right-radius: 0.5rem;
  cursor: pointer;
  z-index: 1001;
  box-shadow: 2px 0 5px rgba(0, 0, 0, 0.1);
  transition: all 0.3s ease;

  &:hover {
    background-color: #34495e;
  }

  &.sidebar-collapsed {
    left: 15px; // Position when sidebar is collapsed
  }
}

sidebar.component.scss

Define styles for the sidebar and menu:

.sidebar {
  background-color: #2c3e50;
  color: #ecf0f1;
  height: 100vh;
  width: 250px;
  position: fixed;
  top: 0;
  left: 0;
  z-index: 1000;
  transition: all 0.3s ease-in-out;
  overflow-x: hidden;
  box-shadow: 2px 0 5px rgba(0, 0, 0, 0.1);
}

.sidebar-header {
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 1.5rem;
  position: relative;
}

.sidebar-logo {
  color: #fff;
  text-decoration: none;
  font-size: 1.5rem;
  font-weight: bold;
  text-align: center;
}

.sidebar-menu {
  padding: 1rem 0;

  ul {
    list-style-type: none;
    padding: 0;
    margin: 0;
  }
}

.sidebar-menu-item {
  position: relative;
}

.sidebar-item {
  display: flex;
  align-items: center;
  color: #ecf0f1;
  text-decoration: none;
  padding: 0.75rem 1rem;
  transition: all 0.2s ease;
  cursor: pointer;

  &:hover {
    background-color: rgba(255, 255, 255, 0.1);
  }

  &.menu-item-active {
    background-color: rgba(255, 255, 255, 0.2);
  }

  i {
    margin-right: 0.75rem;

    &.sidebar-item-arrow {
      margin-left: auto;
      font-size: 0.8rem;
      transition: transform 0.3s ease;

      &.rotated {
        transform: rotate(180deg);
      }
    }
  }

  &-text {
    opacity: 1;
    transition: opacity 0.3s ease-in-out;
  }

  &.has-children {
    position: relative;
  }
}

.sidebar-submenu {
  background-color: rgba(0, 0, 0, 0.1);

  .sidebar-item {
    padding-left: 3rem;
    font-size: 0.9rem;
  }
}

.sidebar-collapsed {
  width: 50px;

  .sidebar-menu-item {
    position: static;
  }

  .sidebar-item {
    i {
      margin-right: 0;
    }
    &-text,
    &-arrow {
      opacity: 0;
      width: 0;
      overflow: hidden;
    }
  }

  .sidebar-submenu {
    display: none;
  }
}

5. Run the Application

Start the development server:

ng serve

Navigate to http://localhost:4200/ to see your sidebar in action.

FAQs

How Do I Customize Sidebar Icons?

Modify the menuItems array in sidebar.component.ts and provide appropriate icon classes.

Can I Add Animations for Menu Expansion?

Yes, use Angular’s animation module to add smooth transitions when menus open and close.

How Do I Adjust Sidebar Width?

Update the width property in sidebar.component.scss for the expanded and collapsed states.

This guide covers all the essential steps to create a functional expandable and collapsible sidebar in Angular. You can further customize the design and functionality to meet your application needs.

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