ask.ts

/**
 * @license
 * Copyright 2016 Google Inc. All rights reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

'use strict';

const readline = require('readline');

function ask(question: string, options: string[]): Promise<string> {
  return new Promise((resolve, reject) => {
    const iface = readline.createInterface(process.stdin, process.stdout);
    const optionsStr = options.map((o, i) => i + 1 + '. ' + o).join('\r\n');

    iface.setPrompt(question + '\r\n' + optionsStr + '\r\nChoice: ');
    iface.prompt();

    iface.on('line', (_answer: string) => {
      const answer = toInt(_answer);
      if (answer > 0 && answer <= options.length) {
        iface.close();
        resolve(options[answer - 1]);
      } else {
        iface.prompt();
      }
    });
  });
}

function toInt(n: string): number {
  const result = parseInt(n, 10);
  return isNaN(result) ? 0 : result;
}

export {ask};