TypeScript Error Handling - Exercises & Solutions

TypeScript Error Handling [12 exercises with solution]

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Following exercises will help you practice error handling techniques in TypeScript, including exception handling, creating custom error classes, and propagating errors through your code.

Exception Handling:

1. Write a TypeScript function that throws an exception when a specified condition is not met. Implement a try-catch block to handle the exception and display an error message.
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2. Write a TypeScript function that calls a non-existent function. Use a try-catch block to catch the resulting error and display a custom error message.  
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3. Write a TypeScript function that parses an integer from a string. Handle potential exceptions caused by invalid input using try-catch.  
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4. Write a TypeScript program that opens a non-existent file using the Node.js 'fs' module. Implement error handling to catch file-not-found exceptions and display an error message. 
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Custom Error Classes:

5. Write a custom TypeScript error class called 'ValidationException' that extends the built-in 'Error' class. Use this custom error class to throw and catch validation errors with custom error messages.  
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6. Write a TypeScript program that reads data from an external API. Create a custom error class, 'ApiError', to handle errors related to API requests. Use this custom error class to catch and display API error messages.  
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7. Write a TypeScript function that performs database operations. Create a custom error class, 'DatabaseError', for handling database-related errors. Use this error class to catch and log database errors.  
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8. Write a TypeScript application that processes user input. Create a custom error class, `InputError`, to handle invalid input errors. Use this error class to validate user input and display appropriate error messages.  
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Error Propagation:

9. Write a TypeScript program that reads data from a file using Node.js. Implement error propagation by handling errors at different levels of your code (e.g., in a function, in middleware, and in the main application).  
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10. Write a TypeScript function that makes multiple API requests in sequence. Handle errors from each request and propagate them to the calling function. Implement logging for all errors.  
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11. Write a TypeScript program that simulates a multi-step workflow. Create custom error classes for each step of the workflow. Implement error propagation to handle and log errors at each step.  
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12. Write a TypeScript application that interacts with a database and performs transactions. Implement error propagation to handle database-related errors throughout the application, ensuring transactions are rolled back.  
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More to Come !

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Do not submit any solution of the above exercises at here, if you want to contribute go to the appropriate exercise page.