useStickToBottom

Designed with AI chat bots in mind

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A lightweight zero-dependency React hook + Component that automatically sticks to the bottom of container and smoothly animates the content to keep it's visual position on screen whilst new content is being added.

Features

• Does not require overflow-anchor browser-level CSS support which Safari does not support.
• Can be connected up to any existing component using a hook with refs. Or simply use the provided component, which handles the refs for you plus provides context - so child components can check isAtBottom & programmatically scroll to the bottom.
• Uses the modern, yet well-supported, ResizeObserver API to detect when content resizes.
  • Supports content shrinking without losing stickiness - not just getting taller.
• Correctly handles Scroll Anchoring. This is where when content above the viewport resizes, it doesn't cause the content currently displayed in viewport to jump up or down.
• Allows the user to cancel the stickiness at any time by scrolling up.
  • Clever logic distinguishes the user scrolling from the custom animation scroll events (without doing any debouncing which could cause some events to be missed).
  • Mobile devices work well with this logic too.
• Uses a custom implemented smooth scrolling algorithm, featuring velocity-based spring animations (with configurable parameters).
  • Other libraries use easing functions with durations instead, but these doesn't work well when you want to stream in new content with variable sizing - which is common for AI chatbot use cases.
  • scrollToBottom returns a Promise which will resolve to true as soon as the scroll was successful, or false if the scroll was cancelled.

Installation

npm install use-stick-to-bottom

Usage

`` Component

import { StickToBottom, useStickToBottomContext } from 'use-stick-to-bottom';

function Chat() {
  return (
    
      
        {messages.map((message) => (
          
        ))}
      

      

      {/* This component uses `useStickToBottomContext` to scroll to bottom when the user enters a message */}
      
    
  );
}

function ScrollToBottom() {
  const { isAtBottom, scrollToBottom } = useStickToBottomContext();

  return (
    !isAtBottom && (
       scrollToBottom()}
      />
    )
  );
}

useStickToBottom Hook

import { useStickToBottom } from 'use-stick-to-bottom';

function Component() {
  const { scrollRef, contentRef } = useStickToBottom();

  return (
    

      

        {messages.map((message) => (
          
        ))}
      

    

  );
}