Question

How to read file line by line in Node.js

Answer 1

const readline = require('readline');
const fs = require('fs');

const rl = readline.createInterface({
    input: fs.createReadStream('log.js')
});

let lineNumber = 0;
rl.on('line', textLine => {
    lineNumber++;
    console.log(`Line: ${lineNumber} ${textLine}`);
});

rl.on('close', () => {
    console.log(`\nTotal lines: ${lineNumber}`);
});


    
/*
run:
  
Line: 1 // The module: log.js
Line: 2 
Line: 3 const events = require('events');
Line: 4 
Line: 5 class Log extends events {
Line: 6    show(s) {
Line: 7      console.log(s);
Line: 8   
Line: 9      // Fire (Raise) an event with arguments:
Line: 10      this.emit('gonodego', { id: 88622, name: 'Elizabeth' });
Line: 11   }
Line: 12 }
Line: 13 
Line: 14 module.exports = Log;

Total lines: 14

*/

 

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