nodejs同步异步文件操作

fs.异步读取

fs.readFile('文件路径'[,选项], function (err, data) {
  if (err) {
    console.log('有错误，错误内容是', errr)
  } else {
    console.log('读入文件正确，内容是', data)
  }
});

fs.同步读取

const fs = require("fs")
let rs = fs.readFileSync('文件路径',"utf8");
console.log(rs)
try {
  const fs = require("fs")
    let rs = fs.readFileSync('文件路径',"utf8");
    console.log(rs)
} catch(err) {
  console.log(err)
}

fs.同步写入

var fs = require("fs");
var fd = fs.openSync("hello.txt", "w");
fs.writeSync(fd, "今天天气真好");
fs.closeSync(fd);

fs.异步写入

var fs = require("fs");
fs.writeFile("hello.txt", "这是通过writeFile写入的内容", { flag: "w" }, function (err) {
    if (!err) {
        console.log("写入成功");
    }
});