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class

assert.default.AssertionError

class AssertionError

Indicates the failure of an assertion. All errors thrown by the node:assert module will be instances of the AssertionError class.

  • actual: unknown

    Set to the actual argument for methods such as ().

  • cause?: unknown

    The cause of the error.

  • code: 'ERR_ASSERTION'

    Value is always ERR_ASSERTION to show that the error is an assertion error.

  • expected: unknown

    Set to the expected argument for methods such as ().

  • generatedMessage: boolean

    Indicates if the message was auto-generated (true) or not.

  • message: string
  • name: string
  • operator: string

    Set to the passed in operator value.

  • stack?: string
  • static stackTraceLimit: number

    The maximum number of stack frames to capture.

  • targetObject: object,
    constructorOpt?: Function
    ): void;

    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();
  • static isError(
    value: unknown
    ): value is Error;

    Check if a value is an instance of Error

    @param value

    The value to check

    @returns

    True if the value is an instance of Error, false otherwise

  • err: Error,
    stackTraces: CallSite[]
    ): any;