NightWatch.js execute() and executeAsync() with input script as a string

inject-script.test.js

/**
 * Examples how to inject scripts on NightWatch.js test.
 * The following test will open a page, inject & run the scripts, and get the results.
 * The injected script will be run synchronously & asynchronously.
 * 
 * Both examples use script as a string since I could not find any example on this. 
 * Normally, you have the input script as a JS function but there are cases where you 
 * have to load & inject external script (e.g third party library).
 */
module.exports = {
  '@tags': ['critical'],

  'Visit main page': client => {
    client.page.mainPage()
      .visitPage();
  },

  'Execute script synchronously': client => {
    const scriptString = `
      return $('.welcome-message').text();
    `;
    const params = [];

    client.execute(scriptString, params, result => {
      console.log('SYNC RESULT: ', result);
    });
  },

  'Execute script asynchronously': client => {
    const scriptString = `
      const done = arguments[arguments.length - 1];
      setTimeout(() => {
        done($('.welcome-message').text());
      }, 2000);
    `;
    const params = [];

    client.executeAsync(scriptString, params, result => {
      console.log('ASYNC RESULT: ', result);
    });
  },

  'Ends test properly': client => {
    client.end();
  }
};