Error objects are thrown when runtime errors occur. The Error object can also be used as a base object for user-defined exceptions. See below for standard built-in error types.


Runtime errors result in new Error objects being created and thrown.

Error is a serializable object, so it can be cloned with structuredClone() or copied between Workers using postMessage().

Error types

Besides the generic Error constructor, there are other core error constructors in JavaScript. For client-side exceptions, see Exception handling statements.


Creates an instance representing an error that occurs regarding the global function eval().


Creates an instance representing an error that occurs when a numeric variable or parameter is outside its valid range.


Creates an instance representing an error that occurs when de-referencing an invalid reference.


Creates an instance representing a syntax error.


Creates an instance representing an error that occurs when a variable or parameter is not of a valid type.


Creates an instance representing an error that occurs when encodeURI() or decodeURI() are passed invalid parameters.


Creates an instance representing several errors wrapped in a single error when multiple errors need to be reported by an operation, for example by Promise.any().

InternalError Non-standard

Creates an instance representing an error that occurs when an internal error in the JavaScript engine is thrown. E.g. "too much recursion".



Creates a new Error object.

Static methods

Error.captureStackTrace() Non-standard

A non-standard V8 function that creates the stack property on an Error instance.

Error.stackTraceLimit Non-standard

A non-standard V8 numerical property that limits how many stack frames to include in an error stacktrace.

Error.prepareStackTrace() Non-standard Optional

A non-standard V8 function that, if provided by usercode, is called by the V8 JavaScript engine for thrown exceptions, allowing the user to provide custom formatting for stacktraces.

Instance properties

These properties are defined on Error.prototype and shared by all Error instances.


The constructor function that created the instance object. For Error instances, the initial value is the Error constructor.

Represents the name for the type of error. For, the initial value is "Error". Subclasses like TypeError and SyntaxError provide their own name properties.

Error.prototype.stack Non-standard

A non-standard property for a stack trace.

These properties are own properties of each Error instance.


Error cause indicating the reason why the current error is thrown — usually another caught error. For user-created Error objects, this is the value provided as the cause property of the constructor's second argument.

columnNumber Non-standard

A non-standard Mozilla property for the column number in the line that raised this error.

fileName Non-standard

A non-standard Mozilla property for the path to the file that raised this error.

lineNumber Non-standard

A non-standard Mozilla property for the line number in the file that raised this error.


Error message. For user-created Error objects, this is the string provided as the constructor's first argument.

Instance methods


Returns a string representing the specified object. Overrides the Object.prototype.toString() method.


Throwing a generic error

Usually you create an Error object with the intention of raising it using the throw keyword. You can handle the error using the try...catch construct:

try {
  throw new Error("Whoops!");
} catch (e) {
  console.error(`${}: ${e.message}`);

Handling a specific error type

You can choose to handle only specific error types by testing the error type with the instanceof keyword:

try {;
} catch (e) {
  if (e instanceof EvalError) {
    console.error(`${}: ${e.message}`);
  } else if (e instanceof RangeError) {
    console.error(`${}: ${e.message}`);
  // etc.
  else {
    // If none of our cases matched leave the Error unhandled
    throw e;

Differentiate between similar errors

Sometimes a block of code can fail for reasons that require different handling, but which throw very similar errors (i.e. with the same type and message).

If you don't have control over the original errors that are thrown, one option is to catch them and throw new Error objects that have more specific messages. The original error should be passed to the new Error in the constructor's options parameter as its cause property. This ensures that the original error and stack trace are available to higher-level try/catch blocks.

The example below shows this for two methods that would otherwise fail with similar errors (doFailSomeWay() and doFailAnotherWay()):

function doWork() {
  try {
  } catch (err) {
    throw new Error("Failed in some way", { cause: err });
  try {
  } catch (err) {
    throw new Error("Failed in another way", { cause: err });

try {
} catch (err) {
  switch (err.message) {
    case "Failed in some way":
    case "Failed in another way":

Note: If you are making a library, you should prefer to use error cause to discriminate between different errors emitted — rather than asking your consumers to parse the error message. See the error cause page for an example.

Custom error types can also use the cause property, provided the subclasses' constructor passes the options parameter when calling super(). The Error() base class constructor will read options.cause and define the cause property on the new error instance.

class MyError extends Error {
  constructor(message, options) {
    // Need to pass `options` as the second parameter to install the "cause" property.
    super(message, options);

console.log(new MyError("test", { cause: new Error("cause") }).cause);
// Error: cause

Custom error types

You might want to define your own error types deriving from Error to be able to throw new MyError() and use instanceof MyError to check the kind of error in the exception handler. This results in cleaner and more consistent error handling code.

See "What's a good way to extend Error in JavaScript?" on StackOverflow for an in-depth discussion.

Warning: Builtin subclassing cannot be reliably transpiled to pre-ES6 code, because there's no way to construct the base class with a particular without Reflect.construct(). You need additional configuration or manually call Object.setPrototypeOf(this, CustomError.prototype) at the end of the constructor; otherwise, the constructed instance will not be a CustomError instance. See the TypeScript FAQ for more information.

Note: Some browsers include the CustomError constructor in the stack trace when using ES2015 classes.

class CustomError extends Error {
  constructor(foo = "bar", ...params) {
    // Pass remaining arguments (including vendor specific ones) to parent constructor

    // Maintains proper stack trace for where our error was thrown (only available on V8)
    if (Error.captureStackTrace) {
      Error.captureStackTrace(this, CustomError);
    } = "CustomError";
    // Custom debugging information = foo; = new Date();

try {
  throw new CustomError("baz", "bazMessage");
} catch (e) {
  console.error(; // CustomError
  console.error(; // baz
  console.error(e.message); // bazMessage
  console.error(e.stack); // stacktrace


ECMAScript Language Specification
# sec-error-objects

Browser compatibility

BCD tables only load in the browser

See also