Xterm.js Readline

This is an xterm-js addon that provides a readline like capability to xterm-js. It allows the creation of cli or repl like interfaces on top of xterm-js.

Large parts of this source are inspired / derived / ported from the MIT licensed rustyline project.

Features

• Multi-line prompt and input
• Extendable syntax highlighting
• Unicode / multi column-width character support

Example

This is a multi-line example that treats any line ending with '&&' as a continuation.

import "xterm/css/xterm.css";
import { Terminal } from 'xterm';
import { Readline } from "xterm-readline";

const term = new Terminal({
  theme: {
        background: "#191A19",
        foreground: "#F5F2E7",
  },
  cursorBlink: true,
  cursorStyle: "block"
});

const rl = new Readline();

term.loadAddon(rl);
term.open(document.getElementById('terminal'));
term.focus();

rl.setCheckHandler((text) => {
  let trimmedText = text.trimEnd();
  if (trimmedText.endsWith("&&")) {
    return false;
  }
  return true;
});

function readLine() {
  rl.read(">")
    .then(processLine);
}

function processLine(text) {
  rl.println("you entered: " + text);
  setTimeout(readLine);
}

readLine();

Cancelling a read

read() accepts an optional AbortSignal. Aborting it rejects the pending read with signal.reason.

const controller = new AbortController();
rl.read(">", { signal: controller.signal }).then(processLine, () => {});
controller.abort();

During a read with a signal, the Ctrl-C handler is also called, so it can abort the read:

rl.setCtrlCHandler(() => controller.abort());

Reads without a signal keep the old behavior: Ctrl-C only clears the line.

Keyboard Shortcuts

Key	Action
Home	Move cursor to the beginning of line
End	Move cursor to end of line
Left	Move cursor one character left
Right	Move cursor one character right
Up	Move cursor up (multi-line edit)
Down	Move cursor down (multi-line edit)
Ctrl-C	Cancel line in progress (additionally call ctrl-c callback if registered)
Ctrl-D, Del	Delete the character under the cursor
Enter	Apply the line, or begin a new line in multiline mode
Alt/Shift Enter	Force add \n to the input
Ctrl-U	Clear line
Ctrl-K	Delete text from cursor to end of line

Demo

A small paren-balanced REPL under demo/ for manual testing. Hot-reloads on src/ edits.

npm install
npm run demo

Real World Uses

• Marwood

License Agreement

If you contribute code to this project, you implicitly allow your code to be distributed under the MIT license.