Node.js Integration

/**
 * Convert Node.js callback-style function to promise-returning function
 * @param nodeFunc - Function following Node callback pattern (err, value)
 * @param options - Boolean for multiple values or Array for named values
 * @returns Promisified version of the function
 */
function denodeify(nodeFunc: Function, options?: boolean | Array): Function;

import { denodeify } from "rsvp";
const fs = require('fs');

// Convert fs.readFile to promise-based
const readFile = denodeify(fs.readFile);

readFile('myfile.txt', 'utf8')
  .then(function(data) {
    console.log('File contents:', data);
  })
  .catch(function(error) {
    console.error('Failed to read file:', error);
  });

// Original callback version would be:
// fs.readFile('myfile.txt', 'utf8', function(err, data) {
//   if (err) console.error(err);
//   else console.log(data);
// });

const request = require('request');

// Default - returns only first success parameter
const requestSimple = denodeify(request);
requestSimple('http://example.com').then(function(response) {
  // Only gets the response object
});

// With `true` - returns all success parameters as array
const requestArray = denodeify(request, true);
requestArray('http://example.com').then(function(result) {
  // result[0] is response object
  // result[1] is body
  console.log('Status:', result[0].statusCode);
  console.log('Body:', result[1]);
});

// With array of names - returns object with named properties
const requestNamed = denodeify(request, ['response', 'body']);
requestNamed('http://example.com').then(function(result) {
  console.log('Status:', result.response.statusCode);
  console.log('Body:', result.body);
});

const express = require('express');
const app = express();

// Bind to preserve `this` context
const render = denodeify(app.render.bind(app));

render('template', { data: 'value' })
  .then(function(html) {
    console.log('Rendered HTML:', html);
  });

const request = denodeify(require('request'));

// Original function properties are preserved
const cookieJar = request.jar(); // Works because of inheritance

request('http://example.com', { jar: cookieJar })
  .then(function(response) {
    // cookieJar now contains cookies from the response
  });

const fs = require('fs');
const readFile = denodeify(fs.readFile);
const writeFile = denodeify(fs.writeFile);

// Chain file operations
readFile('input.txt', 'utf8')
  .then(function(data) {
    const processedData = data.toUpperCase();
    return writeFile('output.txt', processedData, 'utf8');
  })
  .then(function() {
    console.log('File processing complete');
  })
  .catch(function(error) {
    console.error('File operation failed:', error);
  });

// Compare with callback version:
// fs.readFile('input.txt', 'utf8', function(err, data) {
//   if (err) return console.error(err);
//   const processedData = data.toUpperCase();
//   fs.writeFile('output.txt', processedData, 'utf8', function(err) {
//     if (err) return console.error(err);
//     console.log('File processing complete');
//   });
// });

const processFile = denodeify(someNodeFunction);

// Promise arguments are resolved before calling the original function
processFile(
  Promise.resolve('filename.txt'),
  Promise.resolve('utf8')
).then(function(result) {
  // Both arguments were resolved before calling someNodeFunction
});

const fs = require('fs');
const readFile = denodeify(fs.readFile);

readFile('nonexistent.txt')
  .catch(function(error) {
    if (error.code === 'ENOENT') {
      console.log('File not found');
      return 'default content';
    }
    throw error; // Re-throw other errors
  })
  .then(function(content) {
    console.log('Content:', content);
  });

const fs = require('fs');

const readFile = denodeify(fs.readFile);
const writeFile = denodeify(fs.writeFile);
const stat = denodeify(fs.stat);
const readdir = denodeify(fs.readdir);

// Usage
Promise.all([
  readFile('file1.txt', 'utf8'),
  readFile('file2.txt', 'utf8'),
  stat('file3.txt')
]).then(function([content1, content2, stats]) {
  console.log('All operations completed');
});

const { exec } = require('child_process');
const execPromise = denodeify(exec);

execPromise('ls -la')
  .then(function(result) {
    console.log('Command output:', result[0]); // stdout
    console.log('Command errors:', result[1]); // stderr
  })
  .catch(function(error) {
    console.error('Command failed:', error);
  });

// Example with a database library
const db = require('some-db-library');
const query = denodeify(db.query, true); // true for multiple return values

query('SELECT * FROM users WHERE id = ?', [userId])
  .then(function(result) {
    const rows = result[0];
    const fields = result[1];
    console.log('Query results:', rows);
  });