38. What is Webpack and what are its main functions?

Webpack is a module bundler for JavaScript, which transforms modules with dependencies into static assets. It is widely used in the modern front-end ecosystem.

Main functions of Webpack:

1. Bundling: Webpack combines multiple source files (JavaScript, CSS, HTML, etc.) into one or more output files.
2. Transpiling: Using loaders, Webpack can transform modern JavaScript code (ES6+) to ES5-compatible code using Babel.
3. Code Splitting: Webpack allows for code splitting into smaller chunks that are loaded on demand, improving application performance.
4. Resource Optimization: Webpack minifies and optimizes resources like CSS, JavaScript, and images.
5. Dependency Management: It automatically analyzes and manages dependencies between modular files.

Example Webpack configuration:

const path = require('path');

module.exports = {
  entry: './src/index.js',
  output: {
    filename: 'bundle.js',
    path: path.resolve(__dirname, 'dist')
  },
  module: {
    rules: [
      {
        test: /\.js$/,
        exclude: /node_modules/,
        use: {
          loader: 'babel-loader',
          options: {
            presets: ['@babel/preset-env']
          }
        }
      }
    ]
  }
};

Webpack is a powerful tool for managing and optimizing assets in web applications.