Class: BaseError

API / @xmachines/core / errors / BaseError

Defined in: packages/core/src/errors.ts:44

The base class of every typed runtime error of an @xmachines/* package.

BaseError gives each error two structured fields:

scope — the class or the module that threw the error, for example "asDisposable"
code — a stable, machine-readable identifier, for example "CORE_DISPOSE_CONFLICT"

Your application code therefore branches on the type of an error, and it does not parse the .message string. A message changes between releases.

PlayError of @xmachines/play/errors extends this class, and every error of a Play package extends PlayError. A package below the Play protocol, such as this one, extends BaseError directly. err instanceof BaseError therefore matches every typed error of the workspace.

How to catch an error by its type

import { BaseError, DisposeConflictError } from "@xmachines/core/errors";
import { asDisposable } from "@xmachines/core/utils";

try {
  using handle = asDisposable(target, release);
} catch (err) {
  if (err instanceof DisposeConflictError) {
    // err.scope === "asDisposable"
    // err.code  === "CORE_DISPOSE_CONFLICT"
  } else if (err instanceof BaseError) {
    // Every other @xmachines/* error
    console.error(`[${err.scope}:${err.code}] ${err.message}`);
  } else {
    throw err; // Throw an unknown error again
  }
}

Extends

Error

Extended by

Constructors

Constructor

new BaseError(
   scope,
   code,
   message,
   options?
): BaseError;

Defined in: packages/core/src/errors.ts:64

Parameters

Parameter	Type	Description
`scope`	`string`	The class or the module that throws this error.
`code`	`string`	The machine-readable identifier of the error, for example `"CORE_DISPOSE_CONFLICT"`.
`message`	`string`	The description for a person. Never match on it in your code.
`options?`	`ErrorOptions`	The standard `ErrorOptions`. Give `{ cause: originalError }` to make a chain of errors.

Returns

BaseError

Overrides

Error.constructor;

Properties

Property	Modifier	Type	Description	Inherited from	Defined in
`cause?`	`public`	`unknown`	-	`Error.cause`	-
`code`	`readonly`	`string`	A stable, machine-readable identifier of the error. An error code follows the naming convention `<PACKAGE>_<DESCRIPTION>`, and a Play package writes `PLAY_<PACKAGE>_<DESCRIPTION>`. A code stays the same across each patch release and each minor release of one major version. Never match on `.message`. Always match on `.code`, or on the subclass.	-	packages/core/src/errors.ts:56
`message`	`public`	`string`	-	`Error.message`	-
`name`	`public`	`string`	-	`Error.name`	-
`scope`	`readonly`	`string`	The class or the module that threw this error, for example `"asDisposable"`.	-	packages/core/src/errors.ts:46
`stack?`	`public`	`string`	-	`Error.stack`	-
`stackTraceLimit`	`static`	`number`	The `Error.stackTraceLimit` property specifies the number of stack frames collected by a stack trace (whether generated by `new Error().stack` or `Error.captureStackTrace(obj)`). The default value is `10` but may be set to any valid JavaScript number. Changes will affect any stack trace captured after the value has been changed. If set to a non-number value, or set to a negative number, stack traces will not capture any frames.	`Error.stackTraceLimit`	-

Methods

captureStackTrace()

static captureStackTrace(targetObject, constructorOpt?): void;

Defined in: @types/node

Creates a .stack property on targetObject, which when accessed returns a string representing the location in the code at which Error.captureStackTrace() was called.

const myObject = {};
Error.captureStackTrace(myObject);
myObject.stack; // Similar to `new Error().stack`

The first line of the trace will be prefixed with ${myObject.name}: ${myObject.message}.

The optional constructorOpt argument accepts a function. If given, all frames above constructorOpt, including constructorOpt, will be omitted from the generated stack trace.

The constructorOpt argument is useful for hiding implementation details of error generation from the user. For instance:

function a() {
  b();
}

function b() {
  c();
}

function c() {
  // Create an error without stack trace to avoid calculating the stack trace twice.
  const { stackTraceLimit } = Error;
  Error.stackTraceLimit = 0;
  const error = new Error();
  Error.stackTraceLimit = stackTraceLimit;

  // Capture the stack trace above function b
  Error.captureStackTrace(error, b); // Neither function c, nor b is included in the stack trace
  throw error;
}

a();

Parameters

Parameter	Type
`targetObject`	`object`
`constructorOpt?`	`Function`

Returns

void

Inherited from

Error.captureStackTrace;

isError()

static isError(error): error is Error;

Defined in: typescript

Indicates whether the argument provided is a built-in Error instance or not.

Parameters

Parameter	Type
`error`	`unknown`

Returns

error is Error

Inherited from

Error.isError;

prepareStackTrace()

static prepareStackTrace(err, stackTraces): any;

Defined in: @types/node

Parameters

Parameter	Type
`err`	`Error`
`stackTraces`	`CallSite`[]

Returns

any

See

https://v8.dev/docs/stack-trace-api#customizing-stack-traces

Inherited from

Error.prepareStackTrace;