const shell = require('shelljs');

/**
 * Processes a two-element array, modifying a string based on the first element
 * and passing it to a Node.js script via shell.js execution.
 *
 * @param {Array} channels - A two-element array.
 * @returns {string} - Output from the executed Node.js script.
 */
function processAndExecute(channels) {
  if (!Array.isArray(channels) || channels.length < 2) {
    throw new Error("Input must be a two-element array");
  }

  // Commute the string based on the first element in the array
  const modifiedString = `argument-based-on-${channels[0]}`;

  // Execute another Node.js script, passing modifiedString as an argument
  const output = shell.exec(`node anotherScript.js ${modifiedString}`, { silent: true });

  if (output.code !== 0) {
    throw new Error("Error executing script: " + output.stderr);
  }

  return output.stdout;
}

// Example usage:
const channels = ['channelOne', 'channelTwo'];
try {
  const result = processAndExecute(channels);
  console.log("Script Output:", result);
} catch (error) {
  console.error("Error:", error.message);
}