try...catch...finally.md

chapter	12
pageNumber	86
description	try catch finally allows developers to gracefully handle exceptions (errors) that may occur during the execution of a code block and ensure that certain cleanup actions are always executed, regardless of whether an exception was thrown or not.

try...catch...finally

We can add one more construct to try...catch called finally, this code executes in all cases. i.e. after try when there is no error and after a catch in case of error. The syntax for try ...catch...finally is shown below.

try {
   // try to execute the code
} catch (err) {
    // handle errors 
} finally {
   // execute always
}

Running real-world example code.

try {
  alert( 'try' );
} catch (err) {
  alert( 'catch' );
} finally {
  alert( 'finally' );
}

In the above example, the try block is executed first which is then followed by finally as there are no errors.

{% exercise %} Write a function divideNumbers() that takes two arguments numerator and denominator and returns the result of dividing numerator by denominator using following settings.

{% initial %} function divideNumbers(numerator, denominator) { try { // try statement to divide numerator by denominator. } catch (error) { // print error message } finally { // print execution has finished } // return result } let answer = divideNumbers(10, 2);

{% solution %} function divideNumbers(numerator, denominator) { let result; try { result = numerator / denominator; } catch (error) { console.error(Error: ${error}); } finally { console.log('Function finished executing'); } return result; } let answer = divideNumbers(10, 2); {% validation %} assert(answer == 5);

{% context %} {% endexercise %}