posthog-node/src/extensions/error-tracking/type-checking.ts

PostHog Node.js integration

// Portions of this file are derived from getsentry/sentry-javascript by Software, Inc. dba Sentry
// Licensed under the MIT License

import { PolymorphicEvent } from './types'

export function isEvent(candidate: unknown): candidate is PolymorphicEvent {
  return typeof Event !== 'undefined' && isInstanceOf(candidate, Event)
}

export function isPlainObject(candidate: unknown): candidate is Record<string, unknown> {
  return isBuiltin(candidate, 'Object')
}

export function isError(candidate: unknown): candidate is Error {
  switch (Object.prototype.toString.call(candidate)) {
    case '[object Error]':
    case '[object Exception]':
    case '[object DOMException]':
    case '[object WebAssembly.Exception]':
      return true
    default:
      return isInstanceOf(candidate, Error)
  }
}

export function isInstanceOf(candidate: unknown, base: any): boolean {
  try {
    return candidate instanceof base
  } catch {
    return false
  }
}

export function isErrorEvent(event: unknown): boolean {
  return isBuiltin(event, 'ErrorEvent')
}

export function isBuiltin(candidate: unknown, className: string): boolean {
  return Object.prototype.toString.call(candidate) === `[object ${className}]`
}