next.js/packages/next/src/server/web/globals.ts

import type {
  InstrumentationModule,
  InstrumentationOnRequestError,
} from '../instrumentation/types'

declare const _ENTRIES: any

export async function getEdgeInstrumentationModule(): Promise<
  InstrumentationModule | undefined
> {
  const instrumentation =
    '_ENTRIES' in globalThis &&
    _ENTRIES.middleware_instrumentation &&
    (await _ENTRIES.middleware_instrumentation)

  return instrumentation
}

let instrumentationModulePromise: Promise<any> | null = null
async function registerInstrumentation() {
  // Ensure registerInstrumentation is not called in production build
  if (process.env.NEXT_PHASE === 'phase-production-build') return
  if (!instrumentationModulePromise) {
    instrumentationModulePromise = getEdgeInstrumentationModule()
  }
  const instrumentation = await instrumentationModulePromise
  if (instrumentation?.register) {
    try {
      await instrumentation.register()
    } catch (err: any) {
      err.message = `An error occurred while loading instrumentation hook: ${err.message}`
      throw err
    }
  }
}

export async function edgeInstrumentationOnRequestError(
  ...args: Parameters<InstrumentationOnRequestError>
) {
  const instrumentation = await getEdgeInstrumentationModule()
  try {
    await instrumentation?.onRequestError?.(...args)
  } catch (err) {
    // Log the soft error and continue, since the original error has already been thrown
    console.error('Error in instrumentation.onRequestError:', err)
  }
}

let registerInstrumentationPromise: Promise<void> | null = null
export function ensureInstrumentationRegistered() {
  if (!registerInstrumentationPromise) {
    registerInstrumentationPromise = registerInstrumentation()
  }
  return registerInstrumentationPromise
}

function getUnsupportedModuleErrorMessage(module: string) {
  // warning: if you change these messages, you must adjust how dev-overlay's middleware detects modules not found
  return `The edge runtime does not support Node.js '${module}' module.
Learn More: https://nextjs.org/docs/messages/node-module-in-edge-runtime`
}

function __import_unsupported(moduleName: string) {
  const proxy: any = new Proxy(function () {}, {
    get(_obj, prop) {
      if (prop === 'then') {
        return {}
      }
      throw new Error(getUnsupportedModuleErrorMessage(moduleName))
    },
    construct() {
      throw new Error(getUnsupportedModuleErrorMessage(moduleName))
    },
    apply(_target, _this, args) {
      if (typeof args[0] === 'function') {
        return args[0](proxy)
      }
      throw new Error(getUnsupportedModuleErrorMessage(moduleName))
    },
  })
  return new Proxy({}, { get: () => proxy })
}

function enhanceGlobals() {
  if (process.env.NEXT_RUNTIME !== 'edge') {
    return
  }

  // The condition is true when the "process" module is provided
  if (process !== global.process) {
    // prefer local process but global.process has correct "env"
    process.env = global.process.env
    global.process = process
  }

  // to allow building code that import but does not use node.js modules,
  // webpack will expect this function to exist in global scope
  try {
    Object.defineProperty(globalThis, '__import_unsupported', {
      value: __import_unsupported,
      enumerable: false,
      configurable: false,
    })
  } catch {}

  // Eagerly fire instrumentation hook to make the startup faster.
  void ensureInstrumentationRegistered()
}

enhanceGlobals()