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InvariantError

@rotorsoft/act-root

@rotorsoft/act-root / act/src / InvariantError

Class: InvariantError<TState, TEvents, TActions, TKey, TActor>

Defined in: libs/act/src/types/errors.ts:150

Thrown when a business rule (invariant) is violated during action execution.

Invariants are conditions that must hold true for an action to succeed. They're checked after loading the current state but before emitting events. This error provides complete context about what action was attempted and why it was rejected.

Examples​

import { InvariantError } from "@rotorsoft/act";

try {
  await app.do("withdraw",
    { stream: "account-123", actor: { id: "user1", name: "Alice" } },
    { amount: 1000 }
  );
} catch (error) {
  if (error instanceof InvariantError) {
    console.error("Action:", error.action);
    console.error("Reason:", error.description);
    console.error("Current state:", error.snapshot.state);
    console.error("Attempted payload:", error.payload);
  }
}
try {
  await app.do("closeTicket", target, payload);
} catch (error) {
  if (error instanceof InvariantError) {
    // Present friendly message to user
    if (error.description === "Ticket must be open") {
      return { error: "This ticket is already closed" };
    } else if (error.description === "Not authorized") {
      return { error: "You don't have permission to close this ticket" };
    }
  }
}
try {
  await app.do("transfer", target, { to: "account2", amount: 500 });
} catch (error) {
  if (error instanceof InvariantError) {
    logger.error({
      action: error.action,
      stream: error.target.stream,
      actor: error.target.actor,
      reason: error.description,
      balance: error.snapshot.state.balance,
      attempted: error.payload.amount
    }, "Invariant violation");
  }
}

See​

Invariant for defining business rules

Extends​

  • Error

Type Parameters​

TState​

TState extends Schema

State schema type

TEvents​

TEvents extends Schemas

Event schemas type

TActions​

TActions extends Schemas

Action schemas type

TKey​

TKey extends keyof TActions

Action name

TActor​

TActor extends Actor = Actor

Actor type extending base Actor

Constructors​

Constructor​

new InvariantError<TState, TEvents, TActions, TKey, TActor>(action, payload, target, snapshot, description): InvariantError<TState, TEvents, TActions, TKey, TActor>

Defined in: libs/act/src/types/errors.ts:157

Parameters​

action​

TKey

The action that was attempted

payload​

Readonly<TActions[TKey]>

The action payload that was provided

target​

Target<TActor>

The target stream and actor context

snapshot​

Snapshot<TState, TEvents>

The current state snapshot when invariant was checked

description​

string

Human-readable description of why the invariant failed

Returns​

InvariantError<TState, TEvents, TActions, TKey, TActor>

Overrides​

Error.constructor

Properties​

action​

readonly action: TKey

Defined in: libs/act/src/types/errors.ts:159

The action that was attempted

cause?​

optional cause: unknown

Defined in: node_modules/.pnpm/typescript@5.9.3/node_modules/typescript/lib/lib.es2022.error.d.ts:26

Inherited from​

Error.cause

description​

readonly description: string

Defined in: libs/act/src/types/errors.ts:167

Human-readable description of why the invariant failed

message​

message: string

Defined in: node_modules/.pnpm/typescript@5.9.3/node_modules/typescript/lib/lib.es5.d.ts:1077

Inherited from​

Error.message

name​

name: string

Defined in: node_modules/.pnpm/typescript@5.9.3/node_modules/typescript/lib/lib.es5.d.ts:1076

Inherited from​

Error.name

payload​

readonly payload: Readonly<TActions[TKey]>

Defined in: libs/act/src/types/errors.ts:161

The action payload that was provided

snapshot​

readonly snapshot: Snapshot<TState, TEvents>

Defined in: libs/act/src/types/errors.ts:165

The current state snapshot when invariant was checked

stack?​

optional stack: string

Defined in: node_modules/.pnpm/typescript@5.9.3/node_modules/typescript/lib/lib.es5.d.ts:1078

Inherited from​

Error.stack

target​

readonly target: Target<TActor>

Defined in: libs/act/src/types/errors.ts:163

The target stream and actor context

stackTraceLimit​

static stackTraceLimit: number

Defined in: node_modules/.pnpm/@types+node@25.3.0/node_modules/@types/node/globals.d.ts:67

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.

Inherited from​

Error.stackTraceLimit

Methods​

captureStackTrace()​

static captureStackTrace(targetObject, constructorOpt?): void

Defined in: node_modules/.pnpm/@types+node@25.3.0/node_modules/@types/node/globals.d.ts:51

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​

targetObject​

object

constructorOpt?​

Function

Returns​

void

Inherited from​

Error.captureStackTrace

prepareStackTrace()​

static prepareStackTrace(err, stackTraces): any

Defined in: node_modules/.pnpm/@types+node@25.3.0/node_modules/@types/node/globals.d.ts:55

Parameters​

err​

Error

stackTraces​

CallSite[]

Returns​

any

See​

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

Inherited from​

Error.prepareStackTrace