var fs = require("fs"); var nowDate = new Date(); var result = nowDate.toLocaleDateString()+""+ " "+ nowDate.toLocaleTimeString(); fs.appendFile("d:/2/js/hello.txt",result+" ", err => { if (!err) { fs.readFile("d:/2/js/hello.txt", "utf8", (err, data) => { console.log(data); // Hello world }); } });