added solutions to key errors

Author: Alex Jamshidi

Sprint-2/1-key-errors/0.js

@@ -1,13 +1,36 @@
 // Predict and explain first...
+
 //  =============> write your prediction here
+// str is already a declared variable fed into the capitalise function, the function attempts
+// to declare the variable again, this may throw an error.
+
 
 // call the function capitalise with a string input
 // interpret the error message and figure out why an error is occurring
 
+
+// Error:
+
+// let str = `${str[0].toUpperCase()}${str.slice(1)}`;
+// SyntaxError: Identifier 'str' has already been declared
+
+
+/* Original Code:
+
 function capitalise(str) {
   let str = `${str[0].toUpperCase()}${str.slice(1)}`;
   return str;
-}
+} 
+
+*/
 
 // =============> write your explanation here
+// As predicted, an already declared variable cannot be declared again
+
 // =============> write your new code here
+
+function capitalise(str) {
+  str = `${str[0].toUpperCase()}${str.slice(1)}`;
+  return str;
+}
+

Sprint-2/1-key-errors/1.js

@@ -1,10 +1,14 @@
 // Predict and explain first...
-
 // Why will an error occur when this program runs?
+
 // =============> write your prediction here
+// Assuming we define decimalNumber for the function (otherwise that will throw an error)
+// then we run into the same problem as the last exercise, const decimalNumber = 0.5;
+// is trying to define a variable that has already been determined
 
 // Try playing computer with the example to work out what is going on
 
+/* Original code:
 function convertToPercentage(decimalNumber) {
   const decimalNumber = 0.5;
   const percentage = `${decimalNumber * 100}%`;
@@ -13,8 +17,20 @@ function convertToPercentage(decimalNumber) {
 }
 
 console.log(decimalNumber);
+*/
 
 // =============> write your explanation here
+// Uncaught SyntaxError: Identifier 'decimalNumber' has already been declared
+// As predicted the function is trying to declare a variable that has already been determined
 
 // Finally, correct the code to fix the problem
 // =============> write your new code here
+
+function convertToPercentage(decimalNumber) {
+  decimalNumber = 0.5;
+  const percentage = `${decimalNumber * 100}%`;
+
+  return percentage;
+}
+
+console.log(decimalNumber);

Sprint-2/1-key-errors/2.js

@@ -4,17 +4,27 @@
 // this function should square any number but instead we're going to get an error
 
 // =============> write your prediction of the error here
+// num hasn't been defined, that will throw an error
 
+/*
 function square(3) {
-    return num * num;
+    return num3 * num3;
 }
+*/
 
 // =============> write the error message here
+// Uncaught SyntaxError: Unexpected number
 
 // =============> explain this error message here
+// the error appears in the line before, a function has to take defined parameters, these
+// parameters cannot be represented by numbers (or at least begin with numbers)
 
 // Finally, correct the code to fix the problem
 
 // =============> write your new code here
 
+function square(num) {
+    return num * num;
+}
+