karmaFollowers.js

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// WHO SHOULD I FOLLOW FROM ALL MY FOLLOWERS?

// These are my followers + myself
var myFollowers = [john, mary, susan, peter, chris, itsMe];

// Each follower has some followers, and follows some people
function Follower(userId, followers, following) {
this.userId = userId;
this.followers = followers;
this.following = following;
}

// John is very popular, and follows just me!
var john = new Follower("@john", 1000, 1);

// Mary is so-so, follows many and is followed by as many.
var mary = new Follower("@mary", 26, 23);

// Susan is like Mary, but with bigger numbers
var susan = new Follower("@susan", 233, 230);

// Peter follows everybody but nobody follows him.
var peter = new Follower("@peter", 2, 250);

// Chris is... maybe a spammer with few blind followers?
var chris = new Follower("@chris", 25, 2500);

// And now yourself
var itsMe = new Follower(prompt("Your userId"),prompt("How many followers?"),prompt("And how many following?"));

// Let's make some conclusions out of this
Follower.prototype.karma = function() {

	// In principle more followers means more karma
	var karmaQuantity = this.followers / 100;

	// Ratio followers vs following, more is better
	var karmaRatio = this.followers / this.following;
	
	// Following more people means less atention to you
	// Assuming following 300 is the the limit of quality attention
	var followingMany = this.following;
	function karmaAttention(followingMany) {
		var attention = 0.00001;
		if (followingMany < 300) {
			attention = 1 - (Math.sin(Math.PI / 2 * followingMany / 300));
		}
		return attention;
	}
	
	// Magic karma formula
	var karmaValue = karmaQuantity * karmaRatio * karmaAttention(followingMany);
	return karmaValue.toFixed(8);
};

// Let's see what we've got here...
for (i = 0; i < myFollowers.length; i++) {
var followerName = myFollowers[i];
console.log(followerName.userId + " " + followerName.karma());
}

// ToDo:
// Sort the results by karma
// It would be nice to pull real profiles
// Then we can have a one page website for easy I/O.