krazylearner

/////////////antipattern///////////
function Apple (type) {
    this.type = type;
    this.color = "red";
    this.getInfo = function() {
        return this.color + ' ' + this.type + ' apple';
    };
}

///////////CORRECT///////////

krazylearner

//1
///////////Antipattern///////////
function Apple (type) {
    this.type = type;
    this.color = "red";
    // anti-pattern!
    this.getInfo = getAppleInfo;
}
 
// anti-pattern!

krazylearner

What I do on my cloud instances is I redirect port 80 to port 3000 with this command:

sudo iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 80 -j REDIRECT --to-port 3000
Then I launch my Node.js on port 3000. Requests to port 80 will get mapped to port 3000.

You should also edit your /etc/rc.local file and add that line minus the sudo. That will add the redirect when the machine boots up. You don't need sudo in /etc/rc.local because the commands there are run as root when the system boots.

Logs
Use the forever module to launch your Node.js with. It will make sure that it restarts if it ever crashes and it will redirect console logs to a file.

krazylearner

// generates 4 bytes token
var outname = require('crypto').randomBytes(4).toString('hex');	

krazylearner

<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
Redirect 410 /
</IfModule>

krazylearner

Yes, it is a bad practise. A constructor should return an instance of its class, nothing else. It would mess up the new operator and inheritance otherwise.

Moreover, a constructor should only create and initialize a new instance. It should set up data structures and all instance-specific properties, but not execute any tasks. It should be a pure function without side effects if possible, with all the benefits that has.

What if I want to execute things from my constructor? That should go in a method of your class. You want to mutate global state? Then call that procedure explicitly, not as a side effect of generating an object. This call can go right after the instantiation:

var engine = new Engine()
engine.displayPosts();

krazylearner

/*
 * Make a TCP connection to the given IPv4 address.  Arguments:
 *
 *    ip4addr        a string representing a valid IPv4 address
 *
 *    tcpPort        a positive integer representing a valid TCP port
 *
 *    timeout        a positive integer denoting the number of milliseconds

krazylearner

##Patterns for writing functions ###how do you deliver errors to the code that called your function ?

''' Document what your function does, including what arguments it takes (including their types and any other constraints), what it returns, what errors can happen, and what those errors mean. So if you're writing a new function, you have to tell your callers what errors can happen and what they mean. '''

three basic patterns for a function to deliver errors.

Throw, Callback, or EventEmitter

krazylearner

Summary

Given a version number MAJOR.MINOR.PATCH, increment the:

1. MAJOR version when you make incompatible API changes,
2. MINOR version when you add functionality in a backwards-compatible manner, and
3. PATCH version when you make backwards-compatible bug fixes.

##Semantic Versioning Specification (SemVer)

krazylearner

PART 1

1. Styles and themes are time-saving ways to create a consistent look and feel across your Android application.
2. Styles and themes are essentially the same thing: a collection of properties.
3. These properties can be anything from button color to the "wrap content" attribute or the size of your text.
4. The crucial difference is how they’re applied to your project:
5. A style is applied to a View.
6. A theme is applied to individual activities or an entire application.

Why Should I Use Themes and Styles?