If statement to check lowInteger and highInteger are numbers using Number object to represent them as a Number

also I used isInteger boolean condition to check that lowInteger and highInteger is an integer that return an error

an if statement to check that lowInteger and highInteger returns error if they are less than zoro

then if lowInteger is greater than highInteger then assign lowInteger to a temperary holder variable

then assign value of lowInteger to highInteger
then return the value of temperary holder back to highInteger

create a variable that holds the final sumAll
loop through the lowInteger and assign the final value to finalSum then return finalSum

05_sumAll/sumAll.js

@@ -1,6 +1,24 @@
-const sumAll = function() {
+const sumAll = function(highInteger, lowInteger) {
+    if (!Number.isInteger(lowInteger) || !Number.isInteger(highInteger))return "ERROR";
+    if (lowInteger < 0 || highInteger < 0) return "ERROR";
+    if (lowInteger > highInteger){
+        const temp_holder = lowInteger;
+        lowInteger = highInteger;
+        highInteger = temp_holder
+    }
 
+    let finalSum = 0;
+    for (let integers = lowInteger; integers <= highInteger; integers++){
+        finalSum += integers;
+    }
+    return finalSum;
+    
 };
-
+sumAll(1, 4) 
+sumAll(1, 4000)
+sumAll(123, 1)
+sumAll(-10, 4)
+sumAll(10, "90")
+sumAll(10, [90, 1])
 // Do not edit below this line
 module.exports = sumAll;