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How can I create a custom error type to handle specific network failures in a try/catch block in JavaScript?

Asked on Nov 27, 2025

Answer

To create a custom error type in JavaScript for handling specific network failures, you can extend the built-in Error class. This allows you to throw and catch instances of your custom error type in a try/catch block.

<!-- BEGIN COPY / PASTE -->
        class NetworkError extends Error {
            constructor(message) {
                super(message);
                this.name = "NetworkError";
            }
        }

        try {
            // Simulate a network failure
            throw new NetworkError("Failed to fetch data from the server.");
        } catch (error) {
            if (error instanceof NetworkError) {
                console.error("Network error occurred:", error.message);
            } else {
                console.error("An unexpected error occurred:", error);
            }
        }
        <!-- END COPY / PASTE -->

Additional Comment:

The "NetworkError" class extends the built-in "Error" class.
The constructor sets the error message and assigns a custom name to the error type.
In the try block, a "NetworkError" is thrown to simulate a network failure.
The catch block checks if the error is an instance of "NetworkError" to handle it specifically.
This approach helps in distinguishing between different types of errors in your application.

✅ Answered with JavaScript best practices.

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How can I create a custom error type to handle specific network failures in a try/catch block in JavaScript?

Asked on Nov 27, 2025

Answer

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