Node js read file

​Path.join is used to create the file path. There is a directory "files" in the root of the project, where a "test.csv" file is stored. We handle file reading asynchronous.

var path = require('path');
var fs = require('fs');

var filePath = path.join(__dirname, 'files', 'test.csv');

fs.readFile(filePath, 'utf-8', function (err, data) {
    if (err) {
        return console.log("Unable to read file " + err);
    }
    console.log(data + '\n');
});

We can choose to write the filename in the console. The readline module allows us to get user input.

var fs = require('fs');

var readline = require('readline');

/*
 * We need to create a readline interface.
 * The interface takes 2 streams.
 * The input field points to the readable input stream
 * and the output field to the writable output stream. 
 */
var rl = readline.createInterface({
    input: process.stdin,
    output: process.stdout
});

rl.question('File path: ', function (filePath) {
      
    fs.readFile(filePath, 'utf-8', function (err, data) {
        if (err) {
            return console.log("Unable to read file " + err);
        }
        console.log(data + '\n');
    });
    rl.close();
    process.stdin.destroy();    
    
});

You're not supposed to write synchronous javascript, so never use it, but if you want to see the synchronous version of reading a file in node:

var path = require('path'); 
var fs = require('fs'); 
var filePath = path.join(__dirname, 'files', 'test.csv'); 
var file = fs.readFileSync(filePath, 'utf-8'); 
console.log(file);