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The introduction to Reactive Programming you've been missing

(by @andrestaltz)

So you're curious in learning this new thing called Reactive Programming, particularly its variant comprising of Rx, Bacon.js, RAC, and others.

Learning it is hard, even harder by the lack of good material. When I started, I tried looking for tutorials. I found only a handful of practical guides, but they just scratched the surface and never tackled the challenge of building the whole architecture around it. Library documentations often don't help when you're trying to understand some function. I mean, honestly, look at this:

Rx.Observable.prototype.flatMapLatest(selector, [thisArg])

Projects each element of an observable sequence into a new sequence of observable sequences by incorporating the element's index and then transforms an observable sequence of observable sequences into an observable sequence producing values only from the most recent observable sequence.

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const http = require('http');
const urls = process.argv.slice(2, process.argv.length);

let fetchData = function(url){
    return new Promise(function(resolve, reject) { 
    http.get(url, (res)=>{
    let data = '';
    res.setEncoding('utf8');
    //res.resume();
    res.on('data',(chunk)=>{

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const net = require('net');
const portNumber = process.argv[2] || 8000;

let date = new Date();
let month = zeroCheck(date.getUTCMonth() + 1);
let monthDate = zeroCheck(date.getDate());
let hours = zeroCheck(date.getHours());
let minutes = zeroCheck(date.getMinutes());

function zeroCheck(moment){

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

let fileLocation = process.argv[3];
let portNumber = process.argv[2];

const stream = fs.createReadStream(fileLocation);

let server = http.createServer((req,res)=>{
	res.writeHead(200, {'content-type': 'text/plain'});

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const http = require('http');
const url = require('url');
const port = process.argv[2] || 4200;

let body = '';

let server = http.createServer((req, res)=>{

		res.writeHead(200, { 'Content-Type': 'application/json' });
		req.on('data',(chunk)=>{

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<script type="text/x-handlebars" id="components/custom-select">
    <select disabled={{disabled}} class="{{class}}" {{action 'change' on='change'}}>
        {{#if prompt}}
            <option disabled selected={{is-not selection}}>
                {{prompt}}
            </option>
        {{/if}}

        {{#if groups}}
            {{#each groups as |group|}}

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let and const are block scoped, can't be accessed before declaring, otherwise ReferenceError will be thrown. This doesn't happen with var, var is hoisted where let and const are not.

This could lead to bug in program, and it also causes confusion, example http://stackoverflow.com/questions/42803047/why-do-i-get-referenceerror-when-defining-variable-with-let-in-chrome-console#42803047

Detailed explanation : http://stackoverflow.com/questions/33198849/what-is-the-temporal-dead-zone

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App.LibraryRoute = App.ApplicationRoute.extend({
  activate: function () {
    //no longer enter
    this._super();
    only called once on entering a route. 
  },

  beforeModel: function () {
    // any state you want in place before the model is initialized, this is called before any model promises are resolved
    // also could be used to conditionally prevent access to a route by throwing transition.abort

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• Change directory cd
• cd without any argument will take to home directory
• pwd prints the current working directory
• wc is used to count words in file
• cat is used to contcat files, also used to display file contents.

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vs Questions

---

1. http://stackoverflow.com/questions/804115 (rebase vs merge).
2. https://www.atlassian.com/git/tutorials/merging-vs-rebasing (rebase vs merge)
3. https://www.atlassian.com/git/tutorials/undoing-changes/ (reset vs checkout vs revert)
4. http://stackoverflow.com/questions/2221658 (HEAD^ vs HEAD~) (See git rev-parse)
5. http://stackoverflow.com/questions/292357 (pull vs fetch)
6. http://stackoverflow.com/questions/39651 (stash vs branch)
7. http://stackoverflow.com/questions/8358035 (reset vs checkout vs revert)