random-selector

A nodejs module for randomly selecting objects

Status

Features

• Selecting objects with & without replacement
• Select objects with different frequencies

Build

On project folder run

npm install

Run tests

npm test

Run demo

npm start

Usage

Install to your project:

npm install random-selector

Require the selector factory

const selectorFactory = require("random-selector");

Examples of creating selectors

1. Blindly pick out balls in a bag without returning

var normalBag = selectorFactory.createSimpleSelectorWithoutReplacement([
    {color:'red'}, 
    {color:'black'}, 
]);
console.log("Selected ball: ", normalBag.select());
console.log("Selected ball: ", normalBag.select());
console.log("Bag now empty, you've got no balls to select: ", normalBag.select());

2. Blindly pick out balls in a bag then return to the bag

var magicBag = selectorFactory.createSimpleSelectorWithReplacement([
    {color:'red', id:'left'}, 
    {color:'black', id:'right'}, 
]);
console.log("Ball checked: ", magicBag.select());
console.log("Ball checked: ", magicBag.select());
console.log("Still have balls: ", magicBag.select());

3. Flipping an unbiased coin

var chigurhCoin = selectorFactory.createSimpleSelectorWithReplacement(['Head', 'Tail']);
console.log("The most you ever lost in a coin toss? ", chigurhCoin.select());

4. Simulating rolling dice

var dice = selectorFactory.createSimpleSelectorWithReplacement([1, 2, 3, 4, 5, 6]);
var points = Array();
for(let i = 0;i<10;i++)
{
    points.push(dice.select());
}
console.log("Total points after 10 rolls: ", points);

5. daisy meter: a interpersonal relationship evaluation tool base on nature

var daisy = selectorFactory.createSimpleSelectorWithoutReplacement([]);
for(let i=0;i < daisy.getRandomer().getRandomIntBetween(4, 8);i++)
{
    daisy.getElements().push('petal');
}
var meter = true;
while(daisy.select()!=null)
{
    meter = !meter;
    console.log(meter?'He loves me':'He loves me not');
}
if(!meter){
    console.log("He fuckin' hates me, try another daisy!");
}

6. Simulating wheel of fortune:

var fortuneWheel = selectorFactory.createFrequencySelectorWithReplacement(
    [['1000$', 10]
        , ['750$', 10]
        , ['150$', 10]
        , ['400$', 10]
        , ['250$', 10]
        , ['800$', 10]
        , ['100$', 10]
        , ['450$', 10]
        , ['300$', 10]
        , ['600$', 10]
        , ['200$', 10]
        , ['350$', 10]
    ] ///Total frequency is 120
);
console.log("Prize: ", fortuneWheel.select());

///A cheated wheel with 0.5% chance to get 1000$, 50 % chance to get 10$, 49.5% to get stuck (return null)
var realWheel = selectorFactory.createFrequencySelectorWithReplacement(
    [['1000$', 50]
        , ['10$', 5000]
    ]
    , 10000 /*total frequency > sum of all element's freequency: it means selecting may failed (return null)*/
);
console.log("Prize: ", realWheel.select());