now-cli/lib/utils/input/prompt-bool.js

const chalk = require("chalk");

module.exports = (
  label,
  {
    defaultValue = false,
    abortSequences = new Set(["\x03"]),
    resolveChars = new Set(["\r"]),
    yesChar = "y",
    noChar = "n",
    stdin = process.stdin,
    stdout = process.stdout,
    trailing = "\n"
  } = {}
) => {
  return new Promise((resolve, reject) => {
    const isRaw = process.stdin.isRaw;

    stdin.setRawMode(true);
    stdin.resume();

    function restore() {
      console.log(trailing);
      stdin.setRawMode(isRaw);
      stdin.pause();
      stdin.removeListener("data", onData);
    }

    function onData(buffer) {
      const data = buffer.toString();

      if (abortSequences.has(data)) {
        restore();
        return reject(new Error("USER_ABORT"));
      }

      if (resolveChars.has(data[0])) {
        restore();
        resolve(defaultValue);
      } else if (data[0].toLowerCase() === yesChar) {
        restore();
        resolve(true);
      } else if (data[0].toLowerCase() === noChar) {
        restore();
        resolve(false);
      } else {
        // ignore extraneous input
      }
    }

    const defaultText = defaultValue === null
      ? `[${yesChar}|${noChar}]`
      : defaultValue
          ? `[${chalk.bold(yesChar.toUpperCase())}|${noChar}]`
          : `[${yesChar}|${chalk.bold(noChar.toUpperCase())}]`;
    stdout.write(`${chalk.gray("-")} ${label} ${chalk.gray(defaultText)} `);
    stdin.on("data", onData);
  });
};