Reverse Polish Notation (https://www.wikiwand.com/en/Reverse_Polish_notation)

reversePolishNotation.js

const validOps = ['+', '-', '*', '/'];

const compute = (rightOperand, leftOperand, operation) => {
  switch (operation) {
    case '+':
      return leftOperand + rightOperand;
    case '-':
      return leftOperand - rightOperand;
    case '*':
      return leftOperand * rightOperand;
    case '/':
      return leftOperand / rightOperand;
    default:
      return leftOperand;
  }
}

const calculate = (expression) => {
  const stack = []
  const evaluated = expression.split(' ');

  evaluated.forEach(value => {
    if (validOps.indexOf(value) < 0) {
      if(Number.isNaN(value)) {
        console.warn('Unsupported operand! %s was found skipping... ', value);
      } else {
        stack.push(Number(value))
      };
    } else {
      stack.push(compute(stack.pop(), stack.pop(), value));
    }
  });

  return stack.pop();
}