Nodejs file Operation __js

Introducing File System Modules:

var fs = require ("FS");

Working with ReadFile and WriteFile:

Read the contents of the file:

Exports.t1=function () {
	console.log () starts reading the file. ");
	Fs.readfile ("./hello.js", function (err,data) {
		if (err) {return
			console.log (err);
		}
		Console.log (data.tostring ()
	); Asynchronously handles
	
	var data=fs.readfilesync ("./hello.js");
	Console.log (Data.tostring ());
	Console.log ("End of File read.") ");
	Synchronous processing
}

Copy file contents:

Exports.copy1=function () {
	fs.readfile ("./hello.js"), function (err,data) {
		if (err) {return
			Console.log (err);
		}
		Fs.writefile ("./hello_c.js", data);}
	);
	

To operate with Open,read,write:

exports.t2 = function () {var buf = new Buffer (1024);
		Fs.open ("./hello.js", "R", function (err, FD) {(err) {return console.log (err);
			Fs.read (FD, buf, 0, buf.length, 0, function (err, bytes) {if (err) {return console.log (err);
			Console.log ("read" + bytes + "byte");
		Console.log (buf.slice (0, bytes). toString ());

		});
			Fs.close (FD, function (err) {if (err) {return console.log (err);
	}

		});
}); }

Exports.copy2 = function () {
	var buf = new Buffer (1024);
	Fs.open ("./hello.js", "R", function (err, RD) {
		if (err) {return
			console.log (err);
		}

		Fs.read (Rd, buf, 0, buf.length, 0, function (err, bytes) {
			if (err) {return
				console.log (err);
			}
			Fs.open ("./hello_c.js", "w", Function (err, wd) {
				(err) {return
					console.log (err);
				}
				Fs.write (Wd,buf,0,bytes,function (err,written,buffer) {
					fs.close (WD, function (ERR) {
						if (err)
							{ return Console.log (ERR);
						}
					);
					Console.log (written);
					if (err) {return
							console.log (err);
					}
				}

		);}; Fs.close (Rd, function (err) {
			if (err) {return
				console.log (err);
			}
		}
);}

To operate with an event loop:

exports.copy3=function () {var buf = new Buffer (1024); Var eventemitter=new event.
	Eventemitter (); Eventemitter.on ("Copy.star", function () {Fs.open ('./hello.js ', ' R ', function (ERR,RD) {if (err) {return Console.log (er
			R);
		} eventemitter.emit ("Copy.read", RD);
	}); ). On ("Copy.read", function (RD) {Fs.read (Rd,buf,0,buf.length,0,function (err,bytes) {fs.close (Rd,function (Err) {if (
				ERR) {return console.log (err);
			}
			});
			if (err) {return console.log (err);
		} eventemitter.emit ("Copy.write", bytes);
	}); }. On ("Copy.write", function (bytes) {fs.open ("./hello_c.js", "w", Function (ERR,WD) {if (err) {return Console.log (ERR)
			; } fs.write (Wd,buf,0,bytes,function (err,writen,buffer) {fs.close (Wd,function (Err) {if (err) {return consol
					E.log (ERR);
				}
				});
				if (err) {return console.log (err);
		}
			});
	});	
}). Emit ("Copy.star"); }

Error occurs when the content is copied beyond the specified value, so you can use the Createreadstream,createwritestream method.

Exports.t3=function () {
	var read=fs.createreadstream ("./hello.js");
	Read.on ("Data", function (data) {
		Console.log (data.tostring ());
	});
	Read.on ("End", function () {
		console.log () file read ended. ");
	})
}

Exports.copy4=function () {
	var read=fs.createreadstream ("./hello.js");
	var write=fs.createwritestream ("./hello_c.js");
	Read.on ("Data", function (data) {
		write.write (data);
	});
	Read.on ("End", function () {
		write.end ()
	});
	Read.on ("Error", function (err) {
		 console.log (err)}
	)
}	

The simplest way to use a pipe:

Exports.copy5=function () {
	var read=fs.createreadstream ("./hello.js");
	var write=fs.createwritestream ("./hello_c.js");
	Read.pipe (write);

Nodejs File System APIs