There is no shortage of articles about React 16's new lifecycle methods online, but most lack real-world insight. This article explores best practices from actual projects.

Basic Usage

Here is a real-world example:

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

// Middleware
app.use(express.json());

function errorHandler(err, req, res, next) {
  console.error(err.stack);
  res.status(500).json({
    error: process.env.NODE_ENV === "production" ? "Server Error" : err.message,
  });
}

app.get("/api/users", async (req, res, next) => {
  try {
    const users = await User.find();
    res.json(users);
  } catch (err) {
    next(err);
  }
});

app.use(errorHandler);

After promoting this pattern across the team, the results were great and maintenance costs dropped noticeably.

Advanced Techniques

This can be achieved with the following approach:

const http = require("http");
const cluster = require("cluster");
const os = require("os");

if (cluster.isMaster) {
  const numWorkers = os.cpus().length;
  console.log(`Master process ${process.pid}, starting ${numWorkers} workers`);

  for (let i = 0; i < numWorkers; i++) {
    cluster.fork();
  }

  cluster.on("exit", (worker) => {
    console.log(`Worker ${worker.process.pid} exited, restarting`);
    cluster.fork();
  });
} else {
  http
    .createServer((req, res) => {
      res.end(`Worker ${process.pid}`);
    })
    .listen(3000);
}

Pay attention to the performance details in the code above and avoid unnecessary computation.

Real-World Case Study

Refer to the following implementation:

const path = require("path");
const HtmlWebpackPlugin = require("html-webpack-plugin");
const MiniCssExtractPlugin = require("mini-css-extract-plugin");

module.exports = {
  entry: "./src/index.js",
  output: {
    path: path.resolve(__dirname, "dist"),
    filename: "[name].[contenthash:8].js",
  },
  module: {
    rules: [
      {
        test: /\.js$/,
        exclude: /node_modules/,
        use: "babel-loader",
      },
      {
        test: /\.css$/,
        use: [MiniCssExtractPlugin.loader, "css-loader"],
      },
    ],
  },
  optimization: {
    splitChunks: {
      chunks: "all",
      cacheGroups: {
        vendor: {
          test: /[\\/]node_modules[\\/]/,
          name: "vendors",
        },
      },
    },
  },
  plugins: [
    new HtmlWebpackPlugin({ template: "./src/index.html" }),
    new MiniCssExtractPlugin({ filename: "[name].css" }),
  ],
};

This setup has been validated in production and runs reliably.