代码片段

1 十进制转化为十六进制计算器

console.log("-------------------");
console.log("10进制转化为16进制");
console.log("-------------------");
console.log("请输入一个数字: \r\n");

const numRegExp = /^[0-9]*$/;

function warpper(hex) {
  if (!hex) return 0;
  if (hex.length % 2 == 1) return `0${hex}`.toUpperCase();
  return hex.toUpperCase();
}

process.stdin.on("data", (buffer) => {
  const data = buffer.toString();
  if (!numRegExp.test(data.trim())) {
    console.error("无效输入, 请输入一个数字");
  } else {
    const hex = Number(data.trim()).toString(16);
    console.log("16进制结果为: %s \r\n", warpper(hex));
  }
});

2 图片访问服务

const http = require("http");
const fs = require("fs");

const IMAGE_DIR = "./images";
const PORT = 2000;

if (!fs.existsSync(IMAGE_DIR)) fs.mkdirSync(IMAGE_DIR);

http
  .createServer((req, res) => {
    const ip = req.socket.remoteAddress;
    const port = req.socket.remotePort;
    const path = req.url;

    console.log(
      `[${new Date().toLocaleString()}] request from [${ip}:${port}${path}]`
    );

    if (path.startsWith("/image/")) {
      const imageName = path.split("/").filter((v) => !!v)[1];
      fs.readFile(`./images/${imageName}`, "binary", (err, file) => {
        if (err) {
          res.writeHead(404);
          res.end("Image not found");
        } else {
          res.writeHead(200, { "Content-Type": "image/png" });
          res.write(file, "binary");
          res.end();
        }
      });
    } else {
      res.end(JSON.stringify({ code: 0, message: "success", data: null }));
    }
  })
  .listen(PORT);

console.log(`[${new Date().toLocaleString()}] Server running at port ${PORT}`);