nomad/ui/app/utils/classes/exec-command-editor-xterm-adapter.js

const REVERSE_WRAPAROUND_MODE = '\x1b[?45h';
const BACKSPACE_ONE_CHARACTER = '\x08 \x08';

export default class ExecCommandEditorXtermAdapter {
  constructor(terminal, setCommandCallback, command) {
    this.terminal = terminal;
    this.setCommandCallback = setCommandCallback;

    this.command = command;

    this.keyListener = terminal.onKey(e => {
      this.handleKeyEvent(e);
    });

    // Allows tests to bypass synthetic keyboard event restrictions
    terminal.simulateCommandKeyEvent = this.handleKeyEvent.bind(this);

    terminal.write(REVERSE_WRAPAROUND_MODE);
  }

  handleKeyEvent(e) {
    // Issue to handle arrow keys etc: https://github.com/hashicorp/nomad/issues/7463
    if (e.domEvent.key === 'Enter') {
      this.terminal.writeln('');
      this.setCommandCallback(this.command);
      this.keyListener.dispose();
    } else if (e.domEvent.key === 'Backspace') {
      if (this.command.length > 0) {
        this.terminal.write(BACKSPACE_ONE_CHARACTER);
        this.command = this.command.slice(0, -1);
      }
    } else if (e.key.length > 0) {
      this.terminal.write(e.key);
      this.command = `${this.command}${e.key}`;
    }
  }

  destroy() {
    this.keyListener.dispose();
  }
}