Try catch blocks, custom error types, and common debugging techniques in JavaScript, each explained with a short example.
29 cards · basic cards · AI-written, checked twice. Edit anything.
- What is the syntax for a try-catch block?
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try { code that might fail } catch (error) { handle error }- What happens if an error is thrown inside try without a catch?
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The script stops, the error propagates up, and execution halts unless caught higher up- Name three properties available on an Error object
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message, name, stack- What error does accessing an undefined variable throw?
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ReferenceError- What error does calling a non-function throw?
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TypeError- What error is thrown for invalid JSON syntax?
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SyntaxError- What is the purpose of the finally block?
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Code that runs after try or catch, regardless of whether an error occurred- How do you manually throw an error?
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Use the throw keyword: throw new Error('message') or throw someValue- How do you create a custom error type?
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Extend the Error class: class MyError extends Error { constructor(message) { super(message) } }- What does the stack property of an Error contain?
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A string showing the call stack at the point the error was thrown, useful for debugging- What is console.log primarily used for?
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Printing general information to the console for debugging- What is the difference between console.error and console.warn?
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console.error is for errors (red), console.warn is for warnings (yellow or orange)- What does the debugger statement do?
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Pauses code execution at that line when developer tools are open, allowing step-through inspection- How do you catch errors from a Promise?
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Use .catch() method: promise.catch(error => { handle error })- How do you use try-catch with async/await?
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try { const result = await someAsyncFunction() } catch (error) { handle error }
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