wabot/util/capture-stdout.js

Whatsapp Bot Module for automate response and interact whit users

/**
 * @file capture-stdout.js
 * Provides a class to capture stdout, storing the stream in a string.   
 * Useful for testing :)
 *
 * I stole this from Steve Farthing who got it from a gist from Ben Buckman 
 * who got it from Preston Guillory
 *
 * @author Randy Carver
 * @date 7/21/17
 *
 * Copyright © 2017 Blue Otter Software - All Rights Reserved
 * The MyBooks tutorial project is Licensed under the MIT License.
 * See LICENSE.md file in the project root for full license information.
 * {@link https://github.com/rpcarver/mybooks|MyBooks Github Repository }
 * {@link http://blueottersoftware.com/2017/06/19/mybooks-tutorial-index/MyBooks Tutorial Index}
 * {@link https://www.linkedin.com/in/randycarver/|LinkedIn}
 */

/**
 * This class captures the stdout and stores each write in an array of strings.
 */
class CaptureStdout {
    constructor() {
      this._capturedText = [];
      this._orig_stdout_write = null;
    }
  
    /**
     * Starts capturing the writes to process.stdout
     */
    startCapture() {
      this._orig_stdout_write = process.stdout.write;
      process.stdout.write = this._writeCapture.bind(this);
    }
  
    /**
     * Stops capturing the writes to process.stdout.
     */
    stopCapture() {
      if (this._orig_stdout_write) {
        process.stdout.write = this._orig_stdout_write;
      }
    }
  
    /**
     * Private method that is used as the replacement write function for process.stdout
     * @param string
     * @private
     */
    _writeCapture(string) {
      this._capturedText.push(string);
    }
  
    /**
     * Retrieve the text that has been captured since creation or since the last clear call
     * @returns {Array} of Strings
     */
    getCapturedText() {
      return this._capturedText;
    }
  
    /**
     * Clears all of the captured text
     */
    clearCaptureText() {
      this._capturedText = [];
    }
  }
  
  module.exports = CaptureStdout;