A simple RSS Reader with Readline in NodeJS

cli-rss-reader.js

/*
Readline module is used to read and write data in console.
Full docs on Readline - https: //nodejs.org/api/readline.html
    In this example the list of RSS channes from Yandex.news - https: //news.yandex.ru/export.html
    To call the script you should use type: 'node --harmony cmd.js'
*/

// Adding needed modules:
// readline - reads console ine
// request - does http resquests 
// parser - parses the responses
const readline = require('readline');
const r = require('request');
const parser = require('/usr/local/lib/node_modules/xml2json/');

// Script variables:
// currentState - flag showing what news type to show
// items - list of news in the RSS
// rsss - list of RSS litst
var currentState = 'general';
var items = [];
const rsss = [{
    'title': 'Hardware',
    'url': 'https://news.yandex.ru/hardware.rss'
}, {
    'title': 'Science',
    'url': 'https://news.yandex.ru/science.rss'
}, {
    'title': 'Finances',
    'url': 'https://news.yandex.ru/finances.rss'
}, {
    'title': 'Society',
    'url': 'https://news.yandex.ru/society.rss'
}, {
    'title': 'Internet',
    'url': 'https://news.yandex.ru/internet.rss'
}, {
    'title': 'Netherlands',
    'url': 'https://news.yandex.ru/Netherlands/index.rss'
}, {
    'title': 'Football',
    'url': 'https://news.yandex.ru/football.rss'
}, {
    'title': 'Law',
    'url': 'https://news.yandex.ru/law.rss'
}];

//init Readline interface
const rl = readline.createInterface({
    input: process.stdin,
    output: process.stdout
});


//Below there are several handlers 
// - loadChannel, channelAnswers, generalAnswers, loadGeneral
// their names should be pretty self-explanatory

var loadChannel = function(e) {

    currentState = 'channel';

    var ch = JSON.parse(e).rss;
    items = ch.channel.item;

    console.log('|| ', ch.channel.title);
    items.forEach((x, i) => {
        console.log((i + 1) + ' - ' + x.title);
    });

    console.log('>> Select item to read (0 - for level up)');
}

var channelAnswers = function(answer) {
    if (!items[answer]) {
        console.log('Wrong item number');
    } else {
        console.log('|| ', items[(answer - 1)].title);
        console.log(items[(answer - 1)].description);
        console.log('>> Enter next command...');
    }
}


var generalAnswers = function(answer) {
    if (!rsss[answer]) {
        console.log('Wrong channel number');
    }

    r(rsss[(answer - 1)].url, function(error, response, body) {
        if (!error && response.statusCode == 200) {
            loadChannel(parser.toJson(body));
        }
    })
}

var loadGeneral = function() {
    console.log('Please select channel to read out of ' + rsss.length + '\n');
    rsss.forEach((x, i) => {
        console.log((i + 1) + ' - ' + x.title);
    });
    currentState = 'general';
    console.log('>> Enter id from 1 to ' + rsss.length + ':');
}

//Main Readline event handler 
rl.on('line', (answer) => {
    if (answer == 0) {
        loadGeneral();
        return;
    }
    //quit it user presses 'x' or 'q'
    if (answer == 'x' || answer == 'q') {
        console.log('Bye!');
        process.exit(0);
    }

    (currentState == 'general') ? generalAnswers(answer): channelAnswers(answer);
});
/*
This is relatively simple example.You can extend this one or use one of the advanced modules working with cli in NodeJS.
For example this: https: //github.com/chriso/cli
*/
//JS module syntax - default function to call when module file in called
module.exports.default = loadGeneral();