ran npm run tdd & generated TDD

test/solveRPN/solveRPN.js

@@ -0,0 +1,28 @@
+module.exports = rpn => {
+const OPERATORS = {
+'*': (a, b) => a * b,
+'+': (a, b) => a + b,
+'-': (a, b) => a - b,
+'/': (a, b) => a / b,
+'**': (a, b) => a ** b
+};
+const [stack, solve] = [
+[],
+rpn
+.replace(/\^/g, '**')
+.split(/\s+/g)
+.filter(el => !/\s+/.test(el) && el !== '')
+];
+solve.forEach(symbol => {
+if (!isNaN(parseFloat(symbol)) && isFinite(symbol)) {
+stack.push(symbol);
+} else if (Object.keys(OPERATORS).includes(symbol)) {
+const [a, b] = [stack.pop(), stack.pop()];
+stack.push(OPERATORS[symbol](parseFloat(b), parseFloat(a)));
+} else {
+throw `${symbol} is not a recognized symbol`;
+}
+});
+if (stack.length === 1) return stack.pop();
+else throw `${rpn} is not a proper RPN. Please check it and try again`;
+};