edit introduction.md proof.ci.js and error-handling.js

Author: A-O-Emmanuel

exercises/practice/error-handling/.docs/introduction.md

@@ -7,9 +7,19 @@ You will learn how to:
 - Check input types and throw errors for invalid inputs.
 - Throw errors for specific cases (e.g., empty strings).
 - Return the uppercase version of the string if it is valid.
+- Handle and catch errors using a try..catch block
 
-Your function should:
 
-- Throw a `TypeError` if input is not a string.
-- Throw a general `Error` if input is an empty string.
-- Return the uppercase form of the string 'hello'.
+Implement the processString function using a `try…catch` block.
+
+Inside the `try` block:
+
+- If the input is not a string, throw a `TypeError`.
+
+- If the input is an empty string, throw a generic `Error`.
+
+- Otherwise, return the input in `uppercase`.
+
+Inside the `catch` block:
+- console log the `error` message
+- `throw` the `error` so it can be tested for its type.

exercises/practice/error-handling/.meta/proof.ci.js

@@ -1,9 +1,14 @@
 export const processString = (input) => {
-  if (typeof input !== 'string') {
-    throw new TypeError();
+  try {
+    if (typeof input !== 'string') {
+      throw new TypeError('Input must be a string');
+    }
+    if (input === '') {
+      throw new Error('Input cannot be empty');
+    }
+    return input.toUpperCase();
+  } catch (error) {
+    console.log(error.message);
+    throw error;
   }
-  if (input === '') {
-    throw new Error();
-  }
-  return input.toUpperCase();
 };

exercises/practice/error-handling/error-handling.js

@@ -1,6 +1,8 @@
+//
+// This is only a SKELETON file for the 'Error handling' exercise. It's been provided as a
+// convenience to get you started writing code faster.
+//
+
 export const processString = (input) => {
-  //TODO: implement this
-  //should throw TypeError if input is not a string
-  //should throw a general Error if input is an empty string
-  //should return the uppercase version of the string 'hello'
+  throw new Error('Remove this line and implement the function');
 };