Learnyounode - I

01_hello_world.js

 console.log("HELLO WORLD")

02_baby_steps.js

var toPrint = process.argv.slice(2).map(Number);

toPrint = toPrint.reduce(function(pv,cv){
  return pv + cv;
});

console.log(toPrint);

03_my_first_io.js

var fs = require('fs');

var path = process.argv[2];

lFile=fs.readFileSync(path).toString();

lFile = lFile.split('\n');

console.log(lFile.length - 1);

               

04_my_first_async_io.js

var fs = require('fs');

var path = process.argv[2];

fs.readFile(path,function(error,data){
  lFile=data.toString().split('\n');
  console.log(lFile.length - 1);
});

05_filtered_ls.js

var fs = require('fs');

function strEndsWith(str, suffix) {
  suffix = '.' + suffix;
  return str.match(suffix+"$")==suffix;
}

var path = process.argv[2];

var filterKind = process.argv[3];

fs.readdir(path,function(error,data){
  data.forEach(function(line, index){
    if (strEndsWith(line,filterKind)) console.log(line); 
  });
});

  
// \\ // \\ Better Solution // \\ // \\

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

// fs.readdir(process.argv[2], function (err, list) {
//   list.forEach(function (file) {
//     if (path.extname(file) === '.' + process.argv[3])
//       console.log(file)
//   })
// })

06_make_it_modular.js

var extraModule = require('./06a_make_it_modular.js')

extraModule(process.argv[2],process.argv[3], function(err,data){

  data.forEach(function(element){
    console.log(element);
  });

})

06a_make_it_modular.js

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

module.exports = function (dirName, extensionType, callback) {
    
  var result = [];

  fs.readdir(dirName, function (err, list) {
    if (err) {return callback(err, null)};
    list.forEach(function (file) {
      if (path.extname(file) === '.' + extensionType) {
        result.push(file)
      }
    })
    callback(null, result) 
  });
}

07_http_client.js

http = require ('http')

var url = process.argv[2];

http.get(url, function(res) {
  res.setEncoding('utf8');
  res.on('data',function(d){
    console.log(d);
  })
}).on('error', function(e) {
  console.log("Got error: " + e.message);
});

08_http_collect.js

http = require ('http')

var url = process.argv[2];
var data_final = [];
http.get(url, function(res) {
  res.setEncoding('utf8');
  res.on('data',function(d){
    data_final.push(d);
  })
  res.on('end',function(){
    console.log(data_final.join('').length);
    console.log(data_final.join(''));
  })
}).on('error', function(e) {
  console.log("Got error: " + e.message);
});