JavaScript Tutorial
What Is try…catch in JavaScript?
The try…catch statement in JavaScript is used to handle runtime errors without stopping the execution of your program. It allows you to write safer code by catching errors and responding to them properly.
Why Use try…catch?
Without error handling, a single error can break the entire application. Using try…catch helps you:
- Prevent crashes
- Show user-friendly error messages
- Debug issues easily
- Handle unexpected situations
Basic Syntax of try…catch
try {
// Code that may cause an error
} catch (error) {
// Code to handle the error
}
If an error occurs inside try, JavaScript immediately jumps to catch.
Simple try…catch Example
try {
let result = JSON.parse('{name: "John"}');
} catch (error) {
console.log("Invalid JSON format");
}- Prevents the script from crashing
- Displays a meaningful message
Accessing the Error Object
The catch block provides an error object containing useful information.
try {
undefinedFunction();
} catch (error) {
console.log(error.name); // ReferenceError
console.log(error.message); // undefinedFunction is not defined
}Common Error Properties
- name → Type of error
- message → Error description
- stack → Error location
Using try…catch with finally
The finally block runs always, whether an error occurs or not.
try {
console.log("Trying...");
} catch (error) {
console.log("Error occurred");
} finally {
console.log("Execution completed");
}
Useful for:
- Closing resources
- Hiding loaders
- Cleanup actions
try…catch with async / await
try…catch is commonly used with async JavaScript functions.
async function loadData() {
try {
const response = await fetch("https://api.example.com/data");
const data = await response.json();
console.log(data);
} catch (error) {
console.log("Failed to load data");
}
}When try…catch Does NOT Work
- Syntax errors
- Errors outside the try block
- Errors inside setTimeout without wrapping
try {
setTimeout(() => {
undefinedFunction();
}, 1000);
} catch (error) {
console.log("This will NOT catch the error");
}
Best Practices for try…catch
- Use only where errors may occur
- Show meaningful error messages
- Avoid empty catch blocks
- Log errors for debugging
- Don’t overuse try…catch
Common Mistakes
- Catching errors but doing nothing
- Using try…catch for normal logic
- Showing raw error messages to users
- Wrapping entire apps in one try block