ratatui-wasm-backend

A Backend implementation for Ratatui targeting WASM.

The goals of this implementation are:

• A simple implementation of the Ratatui Backend trait which can run in WASM.
• Can run in the browser, or the command-line.
• Uses standard ANSI codes for controlling the terminal. (You'll need a modern terminal app.)

Known issues:

• Probably not the most efficient at the codes that it outputs.
• Not yet well tested. But I'm open to bug reports & PRs!
• When exiting

Usage

The basic process is:

• Create a (ratatui-wasm-backend) AnsiBackend instance. This currently needs 2 arguments:
  • get_size - a callback to get the size of the terminal window
  • stdout_writer - a place to synchronously write bytes to stdout.
• Call its .exclusive() method.
• Create the Ratatui Terminal, passing it the above backend.
• Start your event loop:
  • Process event
  • update application state
  • re-render your TUI
• on exit
  • end the "exclusive" (alternate) terminal mode. (AnsiBackend.normal())

Recommendations

Process stdin in Rust.

You can do it in JavaScript. But for every type of event you need to send across the JavaScript/Rust boundary, you'll potentially need to make a new typescript type, or a new wasm-bindgen method. I just start up an async loop in JavaScript to grab bytes from stdin (Don't forget to set "raw mode"!), and shove bytes into my Rust app for it to handle & rerender.

Example

This repository contains example code that uses this backend. See:

../regtest

Or have a look at the screen recording

Future / To Do

• More efficient terminal code output.
• Some unit tests? 😅
• Move more of the JavaScript setup/teardown into Rust, to reduce boilerplate.
• Link to Rust docs once this crate is published.