Question

What does the throw statement do?

Short answer

Answer: The throw statement is used to manually trigger an exception or error in a program for handling exceptional cases or errors. It allows developers to handle different scenarios, by explicitly specifying when an exception should be raised. An example of using throw statement is in a function that performs division: ```javascript function divide(a, b) { if (b === 0) { throw new Error('Division by zero is not allowed.'); } return a / b; } try { divide(10, 2); divide(10, 0); } catch (error) { console.error(error.message); } ``` In this example, an error is thrown when dividing by zero, preventing the program from crashing and allowing the error to be caught and handled by a try-catch block.

Step-by-step solution

Understanding the Throw Statement

The throw statement is used to manually trigger an exception or error in a program. It allows developers to handle different scenarios, by explicitly specifying when an exception should be raised. When an exception is thrown, the normal flow of the program is interrupted, allowing error handling mechanisms (like try-catch blocks) to take over and resolve the issue.

Purpose of the Throw Statement

Throw statements are used for handling exceptional cases or errors in programs. They serve as a way to signal that something unexpected has occurred and provide a way to handle it gracefully, rather than have the program crash without explanation. Typically, throw statements are used along with try-catch blocks to handle exceptions.

Example of Using Throw

Let's consider an example to demonstrate the use of throw statement. In this example, we have a function called 'divide' which takes two arguments 'a' and 'b' and returns the result of a divided by b. ```javascript function divide(a, b) { if (b === 0) { throw new Error('Division by zero is not allowed.'); } return a / b; } try { divide(10, 2); // 5 (No exception is thrown) divide(10, 0); // Error: Division by zero is not allowed. (As an exception is thrown) } catch (error) { console.error(error.message); } ``` In this example, when the value of 'b' is 0, an error is thrown with the message 'Division by zero is not allowed.'. The error is caught and handled by a try-catch block, which logs the error message to the console instead of causing the program to crash.