如何在Nodejs中使用模块fs文件系统

const fs = require("fs");

fs.open("./db.JSON", "r", (err, fd) => {
    if (err) throw err;
    // 文件操作...
    // 完成操作后，关闭文件
    fs.close(fd, err => {
        if (err) throw err;
    });
});

try {
    const buf = fs.readFileSync("./package.json");
    console.log(buf.toString("utf8"));
} catch (error) {
    console.log(error.message);
}

fs.readFile("./package.json", (err, data) => {
    if (err) throw err;
    console.log(data.toString("utf8"));
});

function readFilePromise(path, encoding = "utf8") {
    const promise = new Promise((resolve, reject) => {
        fs.readFile(path, (err, data) => {
            if (err) return reject(err);
            return resolve(data.toString(encoding));
        });
    });
    return promise;
}

readFilePromise("./package.json").then(res => console.log(res));

const fsPromises = require("fs").promises;

fsPromises
    .readFile("./package.json", {
        encoding: "utf8",
        flag: "r"
    })
    .then(console.log)
    .catch(console.error);

const fsPromises = require("fs").promises;

async function main() {
    const dir = await fsPromises.opendir(".");
    let dirent = null;
    while ((dirent = await dir.read()) !== null) {
        console.log(dirent.name);
    }
}

main();

fs.stat("./package.json", (err, stats) => {
    if (err) throw err;
    console.log(stats);
});

const rs = fs.createReadStream("./package.json");
let content = "";

rs.on("open", () => {
    console.log("start to read");
});

rs.on("data", chunk => {
    content += chunk.toString("utf8");
});

rs.on("close", () => {
    console.log("finish read, content is:\n", content);
});

function copyBigFile(src, target) {
    fs.createReadStream(src).pipe(fs.createWriteStream(target));
}