Decimal to roman numeral converter in node js

Js program for Decimal to roman numeral converter. Here more solutions.

//  Node Js program for
//  Conversion from Decimal to roman number
class Perform
{
    // Display roman value of n
    show(n)
    {
        switch (n) {
            // Test Cases
            case 1:
                this.ans += "I";
                break;
            case 4:
                this.ans += "IV";
                break;
            case 5:
                this.ans += "V";
                break;
            case 9:
                this.ans += "IX";
                break;
            case 10:
                this.ans += "X";
                break;
            case 40:
                this.ans += "XL";
                break;
            case 50:
                this.ans += "L";
                break;
            case 90:
                this.ans += "XC";
                break;
            case 100:
                this.ans += "C";
                break;
            case 400:
                this.ans += "CD";
                break;
            case 500:
                this.ans += "D";
                break;
            case 900:
                this.ans += "DM";
                break;
            case 1000:
                this.ans += "M";
                break;
        }
    }
    select(number, collection, size)
    {
        var n = 1;
        var i = 0;
        for (
        i = 0; i < size; ++i)
        {
            if (number >= collection[i])
            {
                n = collection[i];
            }
            else
            {
                break;
            }
        }
        this.show(n);
        // Reduce the value of number
        return number - n;
    }
    roman(number)
    {
        if (number <= 0)
        {
            // When is not a natural number
            return;
        }
        this.ans = "";
      	var num = number;
        // Base case collection
        var collection = [1, 4, 5, 9, 10, 40, 50, 90, 100, 400, 500, 900, 1000];
        // Get the size of collection
        var size = collection.length;

        while (number > 0)
        {
            number = this.select(number, collection, size);
        }
        console.log(" " + num + " : " +this.ans);
    }
}
function main()
{
    var task = new Perform();
    // Test Case
    task.roman(10);
    task.roman(18);
    task.roman(189);
    task.roman(604);
    task.roman(982);
    task.roman(3000);
}
 // Start program execution
main();

Output

 10 : X
 18 : XVIII
 189 : CLXXXIX
 604 : DCIV
 982 : DMLXXXII
 3000 : MMM