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Design Autocomplete

Requirements​

Functional Requirements​

  • Provide suggestions as the user types
  • Display suggestions in a dropdown menu
  • Allow the user to select a suggestion
  • Update the input field with the selected suggestion
  • Allow the user to submit the form with the selected suggestion
  • Handle large datasets efficiently
  • Allow navigation using keyboard (arrows, Enter, Esc)
  • Clear the input field by clicking on the x button
  • Allow the user to dismiss the dropdown menu by clicking outside of it
  • Provide a loading indicator while fetching suggestions

Non Functional Requirements​

  • Low latency for suggestions
  • High availability
  • Scalable to handle large number of users
  • Responsive design for different screen sizes
  • Support for internationalization
  • Support for accessibility (screen readers, keyboard navigation)
  • Support for mobile devices

System Design​

Architecture​

The autocomplete system can be divided into the following components:

  1. Frontend: The user interface that captures user input and displays suggestions.
  2. Backend: The server that processes user input and returns suggestions.
  3. Database: The storage system for the suggestions data.
  4. Cache: An in-memory cache to store frequently accessed suggestions.
  5. API Gateway: A service that routes requests to the appropriate backend service.
  6. Load Balancer: Distributes incoming traffic across multiple backend servers.
  7. CDN: Delivers static assets like images, CSS, and JavaScript files to users.
  8. Monitoring: Tracks system performance, logs, and metrics to identify issues and optimize performance.

Frontend Components​

The frontend application should be organized into the following components:

  1. Input Field: Captures user input and displays suggestions.
  2. Dropdown Menu: Displays suggestions based on user input.
  3. Loading Indicator: Shows a loading spinner while fetching suggestions.
  4. Clear Button: Clears the input field.
  5. Event Handlers: Handles user interactions like selecting a suggestion, submitting the form, and dismissing the dropdown menu.
  6. Keyboard Navigation: Allows users to navigate the dropdown menu using keyboard shortcuts.
  7. Accessibility Features: Supports screen readers, keyboard navigation, and other accessibility features.
  8. Responsive Design: Adapts to different screen sizes and devices.