Node.js Tutorial for Beginners 8 - Reading and Writing Files using fs module

File I/O is provided by simple wrappers around standard POSIX functions. To use this module do require('fs'). All the methods have asynchronous and synchronous forms.

The asynchronous form always takes a completion callback as its last argument. The arguments passed to the completion callback depend on the method, but the first argument is always reserved for an exception. If the operation was completed successfully, then the first argument will be null or undefined.

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[Batman-wm]

Sir what i will do when we have data in JSON file?? How to read ??

[alexm]

I am probably missing something very obvious but... There are tons of videos dedicated to this topic on YouTube, but nobody (at least, i was not able to find) dedicates a few seconds to explain what the prerequisites are. What kind of editor you use? Which steps to be performed to bring this screen up? Any alternative editors to recognize fs module objects? Without knowing the basics the value of the entire video is drastically deflating, since the most-straight way in learning programming is a practice.

[cicerogomesalves]

How do I get this data in a html/js file???

[rishikamehta]

A bug here: This asynchronous method is not working as read_string var is void. So undefined is showing up on newly written file. i am not able to solve this bug. Plz help.

[daniellajohansson]

The last example don't work for me. I get the printout ->

_the file is read_
_success!_
_I am going to write someshing._
_I am going to write someshing._
_... and so on..._

And in the test3.txt I get ->

_undefined_

[amanchouhan]

var fs = require('fs');

var read_string = fs.readFileSync('pdf.txt', 'utf8');
console.log("read string");
pls help i only got the outpu of console note my .txt
file