messageOptional

A human-readable description of the error.

optionsOptional

An object that has the following properties:

causeOptional

A value indicating the specific cause of the error, reflected in thecause property. When catching and re-throwing an error with a more-specific or useful error message, this property can be used to pass the original error.

fileNameOptionalNon-standard

The path to the file that raised this error, reflected in thefileName property. Defaults to the name of the file containing the code that called theError() constructor.

lineNumberOptionalNon-standard

The line number within the file on which the error was raised, reflected in thelineNumber property. Defaults to the line number containing theError() constructor invocation.

WhenError is used like a function, that is withoutnew, it will return anError object.Therefore, a mere call toError will produce the same output that constructing anError object via thenew keyword would.

const x = Error("I was created using a function call!");// above has the same functionality as followingconst y = new Error('I was constructed via the "new" keyword!');

It is sometimes useful to catch an error and re-throw it with a new message.In this case you should pass the original error into the constructor for the newError, as shown.

try {  frameworkThatCanThrow();} catch (err) {  throw new Error("New error message", { cause: err });}

For a more detailed example seeError > Differentiate between similar errors.

JavaScript only tries to readoptions.cause ifoptions is an object — this avoids ambiguity with the other non-standardError(message, fileName, lineNumber) signature, which requires the second parameter to be a string. If you omitoptions, pass a primitive value asoptions, or pass an object without thecause property, then the createdError object will have nocause property.

// Omitting optionsconst error1 = new Error("Error message");console.log("cause" in error1); // false// Passing a primitive valueconst error2 = new Error("Error message", "");console.log("cause" in error2); // false// Passing an object without a cause propertyconst error3 = new Error("Error message", { details: "http error" });console.log("cause" in error3); // false

• Polyfill ofError withcause support incore-js
• es-shims polyfill of Errorcause
• throw
• try...catch
• Error causes on v8.dev (2021)