calculator & palindromes projects

calculator/calculator.js

@@ -1,32 +1,50 @@
-function add () {
-	
+function add(a, b) {
+  return a + b;
 }
 
-function subtract () {
-	
+function subtract(a, b) {
+  return a - b;
 }
 
-function sum () {
+function sum(arr) {
+  let sum = 0;
+  arr.forEach((num) => {
+    sum += num;
+  });
 
+  return arr.length == 0 ? 0 : sum;
 }
 
-function multiply () {
+function multiply(arr) {
+	let product = 1;
+  arr.forEach((num) => {
+    product *= num;
+  });
 
+  return arr.length == 0 ? 0 : product;
 }
 
-function power() {
-	
+function power(num, pow) {
+	let exponent = 1
+	for (let i = 0; i < pow; i++) {
+		exponent *= num;		
+	}
+	return exponent;
 }
 
-function factorial() {
-	
+function factorial(n) {
+	let facto = 1;
+	for (let i = 0; i < n; i++) {
+		facto = n * factorial(n-1);		
+	}
+	return n == 0 || n == 1 ? 1 : facto;
 }
 
 module.exports = {
-	add,
-	subtract,
-	sum,
-	multiply,
-    power,
-	factorial
-}
+  add,
+  subtract,
+  sum,
+  multiply,
+  power,
+  factorial,
+};

palindromes/palindromes.js

@@ -1,5 +1,16 @@
-const palindromes = function() {
+const palindromes = function (str) {
+  let strippedStr = str.toLowerCase().replace(
+    /(~|`|!|@|#|$|%|^|&|\*|\(|\)|{|}|\[|\]|;|:|\"|'|<|,|\.|>|\?|\/|\\|\||-|_|\+| |=)/g,
+    ""
+  );
+  let splitStr = strippedStr.split("");
+  let reversedStr = [];
 
-}
+  for (let i = splitStr.length - 1; i >= 0; i--) {
+    reversedStr.push(splitStr[i]);
+  }
+//  return [splitStr, reversedStr, JSON.stringify(splitStr), JSON.stringify(reversedStr)];
+  return JSON.stringify(splitStr) === JSON.stringify(reversedStr) ? true : false;
+};
 
-module.exports = palindromes
+module.exports = palindromes;