Interview test I had

interview test

'use strict';

function Calculator(){
}

Calculator.prototype.add = function( int1, int2 ){
	return int1 + int2;
};


Calculator.prototype.subtract = function( int1, int2 ){
	return  int1 - int2;
};


Calculator.prototype.multiply = function( int1, int2 ){
	return int1 * int2;
};


Calculator.prototype.divide = function( int1, int2 ){
	if( int2 === 0 ){
		return NaN;
	} else {
		return int1/int2;
	}
};


var calculator = new Calculator();

console.log( calculator.add(1,2) );
console.log( calculator.subtract(9,2) );
console.log( calculator.multiply(4,3) );
console.log( calculator.divide(10,2) );
console.log( calculator.divide(5,0) );


function ScientificCalculator(){
}

ScientificCalculator.prototype = Object.create(Calculator.prototype);
ScientificCalculator.prototype.constructor = ScientificCalculator;


ScientificCalculator.prototype.sin = function( int ){
	return Math.sin(int);
};

ScientificCalculator.prototype.cos = function( int ){
	return Math.cos(int);
};

ScientificCalculator.prototype.tan = function( int ){
	return Math.tan(int);
};

ScientificCalculator.prototype.log = function( int ){
	return Math.log(int);
};


var calculator = new ScientificCalculator();

console.log(calculator instanceof Calculator);
console.log(calculator instanceof ScientificCalculator);
console.log(calculator.sin( Math.PI / 2 ));
console.log(calculator.cos( Math.PI) );
console.log(calculator.tan( 0 ) );
console.log(calculator.log( 1 ));


var withExponents = function(){
	this.pow = function( int1, int2 ){
		return Math.pow( int1, int2 );
	};
	this.multiplyExp = function( intArr1, intArr2 ){
		return Math.pow( intArr1[0], intArr1[1] ) * Math.pow( intArr2[0], intArr2[1]  );
	};
	this.divideExp = function( intArr1, intArr2 ){
		return Math.pow( intArr1[0], intArr1[1] ) / Math.pow( intArr2[0], intArr2[1]  );
	};
};


var calculator = new Calculator();
withExponents.call( calculator );

console.log( calculator.pow(2,3) );
console.log( calculator.multiplyExp( [2,3], [2,4] ) );
console.log( calculator.divideExp( [2,3], [2,5] ) );


function delay( delayNum, obj, method, args ){
	return new Promise(function(resolve, reject) { 
         if (typeof obj[method] === 'function'){
            setTimeout(
                function() {
                  // We fulfill the promise !
                  resolve(console.log('obj', obj[method](args[0], args[1])));
             }, delayNum);
         } else {
             reject();
         }  
    });
}

var calculator = new Calculator();

console.log(delay( 1400, calculator, 'add', [10,5]));
console.log(delay( 1400, calculator, 'subtract', [9,5]));
console.log(delay( 1400, calculator, 'sqrt', [2,2]));