Class: PlayError

Defined in: packages/play/src/errors.ts:62

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

PlayError gives each error two structured fields:

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

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

The error codes

An @xmachines/* package that defines typed subclasses exports them from an "./errors" subpath:

Package	Import
`@xmachines/play`	`@xmachines/play/errors`
`@xmachines/play-router`	`@xmachines/play-router/errors`
`@xmachines/play-vue-router`	`@xmachines/play-vue-router/errors`
`@xmachines/play-xstate`	`@xmachines/play-xstate/errors`

The root @xmachines/play exports PlayError itself, and it is the base of every subclass above.

How to catch an error by its type

import { PlayError } from "@xmachines/play";
import { RouterSyncError } from "@xmachines/play-router/errors";

try {
  bridge.connect();
} catch (err) {
  if (err instanceof RouterSyncError) {
    // err.scope === "RouterBridgeBase"
    // err.code  === "PLAY_ROUTER_SYNC_FAILED"
    // err.cause  — the original error of the failed synchronization
    reportToMonitoring(err);
  } else if (err instanceof PlayError) {
    // Every other @xmachines/* error
    console.error(`[${err.scope}:${err.code}] ${err.message}`);
  } else {
    throw err; // Throw an unknown error again
  }
}

How to extend PlayError

import { PlayError } from "@xmachines/play";

export class MyPackageError extends PlayError {
  constructor(message: string, options?: ErrorOptions) {
    super("MyScope", "MY_PACKAGE_ERROR_CODE", message, options);
    this.name = "MyPackageError";
  }
}

Extends

Error

Extended by

NonNullableError

Constructors

Constructor

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

Defined in: packages/play/src/errors.ts:82

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 `"PLAY_ROUTER_SYNC_FAILED"`.
`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

PlayError

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 `PLAY_<PACKAGE>_<DESCRIPTION>`. It 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/play/src/errors.ts:74
`message`	`public`	`string`	-	`Error.message`	-
`name`	`public`	`string`	-	`Error.name`	-
`scope`	`readonly`	`string`	The class or the module that threw this error, for example `"RouterBridgeBase"`.	-	packages/play/src/errors.ts:64
`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;