write to file line by line js code example

Example 1: how to right plain text format file in node js

var fs = require('fs')
var logger = fs.createWriteStream('log.txt', {
  flags: 'a' // 'a' means appending (old data will be preserved)
})

logger.write('some data') // append string to your file
logger.write('more data') // again
logger.write('and more') // again

Example 2: node.js read text file line by line

const readline = require('readline');

const readInterface = readline.createInterface({
        input: fs.createReadStream('name.txt'),
        output: process.stdout,
        console: false
    });

 for await (const line of readInterface) {
        console.log(line);
    }
//or
readInterface.on('line', function(line) {
    console.log(line);
});