Design an AutoComplete Widget | FrontEnd System Design Interview

Today let’s look at a commonly asked frontend system design interview question — Design an Autocomplete/Typeahead widget.

Autocomplete widget can be seen almost everywhere, google uses it, facebook uses it and AWS use it. It provides a search experience by providing suggestions relevant to user’s query. I made a video if you prefer the video format.

Table of contents

• Requirements
• Component Architecture
• Component APIs
• Data flow
• Cache
• Optimizations
• Accessibility

Requirements

1. Should return a list of top suggestions, based on user input
2. Suggestions should be ordered based on user input’s recency and frequency
3. The autocomplete widget should have great extensibility
4. Performance
5. Cross-browser compatibility

Component architecture

Let’s first take a look at the component architecture,