Calculator

calculator.js

// Calculator

const operations = {
  '+': (...nums) => nums.reduce((acc, num) => acc + num),
  '*': (...nums) => nums.reduce((acc, num) => acc * num),
}

const calculatorCreator = (additionalOperations = {}) => {
  const calculator = (...elements) => {
    const operator = elements[elements.length-1];
    let inputs = elements.slice(0, elements.length -1);

    inputs = inputs.map(input => Array.isArray(input)
      ? calculator(...input)
      : input
    );

    const totalOpeations = Object.assign({}, operations, additionalOperations);

    return totalOpeations[operator](...inputs);
  };

  return calculator;
}

const simpleCalculator = calculatorCreator();
console.log(simpleCalculator(2, 5, '+')) // 7
console.log(simpleCalculator(3, [2, 5, '*'], '+')); // 13
console.log(simpleCalculator([2, 5, 4, '+'], 3, '*')); // 33
const input1 = [1, 2, '+']; // 3
const input2 = [input1, 3, '*']; // 9
console.log(simpleCalculator(input2, 2, '*')); // 18


const options = {
  mean: (...nums) => (nums.reduce((acc, num) => acc + num) / nums.length),
};
console.log(calculatorCreator(options)(1, 2, 4, 'mean'));