Error objects in JavaScript provide detailed information about runtime errors. They help identify what went wrong, where it happened, and why it failed. JavaScript includes a base Error object and several built-in error types for common failure scenarios.
What Is an Error Object in JavaScript?
An Error object represents a runtime error.
It contains information such as the error message and stack trace.
Explanation:
Creates a custom error with a message that describes the problem.
Common Built-in Error Types
| Error Type | When It Occurs |
|---|---|
Error | Generic error |
TypeError | Wrong data type used |
ReferenceError | Variable is not defined |
RangeError | Value out of allowed range |
SyntaxError | Invalid code syntax |
URIError | Invalid URI handling |
Error Object Properties
| Property | Meaning |
|---|---|
name | Type of error |
message | Description of the error |
stack | Call stack (debug info) |
Explanation:
Accesses the error type and error message inside the catch block.
Creating Custom Error Objects
Explanation:
Throws a custom error when division by zero is attempted.
Throwing Specific Error Types
Explanation:
Throws a TypeError to describe an invalid data type.
Handling Error Objects with try...catch
Explanation:
Catches the error and prevents the program from crashing.
When to Use Error Objects
-
Validate user input
-
Handle API or parsing failures
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Prevent application crashes
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Provide meaningful error messages
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Debug runtime issues
Common Mistakes with Error Objects
-
Throwing strings instead of
Errorobjects -
Ignoring the error message and stack
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Catching errors without handling them
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Exposing technical messages directly to users
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Overusing custom errors for normal logic
Summary
Error objects in JavaScript provide structured information about runtime failures. By using built-in error types, accessing properties like name and message, and throwing meaningful custom errors, error handling becomes clearer, safer, and easier to debug in JavaScript applications.