function ValidateEmail(inputText)
{
var mailformat = /^[a-zA-Z0-9.!#$%&'*+/=?^_`{|}~-]+@[a-zA-Z0-9-]+(?:\.[a-zA-Z0-9-]+)*$/;
if(inputText.value.match(mailformat))
{
alert("Valid email address!");
document.form1.text1.focus();
return true;
}
else
{
alert("You have entered an invalid email address!");
document.form1.text1.focus();
return false;
}
}

First, clear the npm cache: npm cache clean -f.
Install n, Node's version manager: npm install -g n.

const fs = require('fs');

fs.writeFile("/tmp/test", "Hey there!", function(err) {
if(err) {
return console.log(err);
}
console.log("The file was saved!");
});
here we are importing fs module by using rquire to write and read fle data