WebAssembly.RuntimeError

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since October 2017.

The WebAssembly.RuntimeError object is the error type that is thrown whenever WebAssembly specifies a trap.

Constructor

WebAssembly.RuntimeError(): Creates a new WebAssembly.RuntimeError object.

Instance properties

WebAssembly.RuntimeError.prototype.message: Error message. Inherited from Error.
WebAssembly.RuntimeError.prototype.name: Error name. Inherited from Error.
WebAssembly.RuntimeError.prototype.cause: Error cause. Inherited from Error.
WebAssembly.RuntimeError.prototype.fileNameNon-standard: Path to file that raised this error. Inherited from Error.
WebAssembly.RuntimeError.prototype.lineNumberNon-standard: Line number in file that raised this error. Inherited from Error.
WebAssembly.RuntimeError.prototype.columnNumberNon-standard: Column number in line that raised this error. Inherited from Error.
WebAssembly.RuntimeError.prototype.stackNon-standard: Stack trace. Inherited from Error.

Instance methods

WebAssembly.RuntimeError.prototype.toString(): Returns a string representing the specified Error object. Inherited from Error.

Examples

Creating a new RuntimeError instance

The following snippet creates a new RuntimeError instance, and logs its details to the console:

try { throw new WebAssembly.RuntimeError("Hello", "someFile", 10); } catch (e) { console.log(e instanceof WebAssembly.RuntimeError); // true console.log(e.message); // "Hello" console.log(e.name); // "RuntimeError" console.log(e.fileName); // "someFile" console.log(e.lineNumber); // 10 console.log(e.columnNumber); // 0 console.log(e.stack); // returns the location where the code was run }

Specifications

Specification
WebAssembly JavaScript Interface # exceptiondef-runtimeerror
ECMAScript® 2026 Language Specification # sec-native-error-types-used-in-this-standard