es6-stringcalc.js

"use strict";

// Classes. A bit of sugar over prototype based OO pattern
class StringCalc {

    // COnstructor.. just an excuse to use one really
    constructor(decimalPrecision, calcName) {
        this.decimalPrecision = decimalPrecision;
        this.calcName = calcName;
        this.sumTotal = 0;
    }

    add(stringInput) {

        if (stringInput == "0" || stringInput == "")
        {
            return 0;
        }

        // Let.. The new var. Mutable variable (simular to functional langs with mutable and unmutable variables)
        let stringNumbers = stringInput.split(",");
        this.sumTotal = 0;

        // Arrow statement body (simular to c# lambda expresions)
        stringNumbers.forEach(v => {
            this.sumTotal = this.sumTotal + parseInt(v);
        });

        return this.sumTotal;
    }

}


class StringCalcDivision extends StringCalc {

    constructor(decimalPrecision, calcName) {
        // Super calls the base class
        super(decimalPrecision, calcName);
        this.newProperty = 'whatever';
    }

    // Add a new method
    divide(stringInput) {

        if (stringInput == "0" || stringInput == "") {
            return 0;
        }

        let stringNumbers = stringInput.split(",");

        this.sumTotal = stringNumbers[0] / stringNumbers[1]

        return this.sumTotal;
    }

}