Datadog React Native Babel instrumentation causes dayjs.default.default is not a function in Expo apps

[sabreu-teknorix]

Integrating the Datadog React Native SDK in an Expo application introduces a runtime error where modules exporting a default function (e.g., dayjs) are wrapped incorrectly during bundling. The resulting runtime error is:

0, dayjs.default.default is not a function (it is undefined)

The error only occurs when the Datadog instrumentation is enabled. Without the Datadog Babel/Metro integration the application works normally.

Environment

• Expo SDK: ^54.0.7
• React Native: 0.81.5
• Datadog React Native SDK: latest
• Platform: Android
• Metro bundler
• Expo Router
• NativeWind

Observed Behavior

During bundling and runtime execution, the dayjs import becomes:

dayjs.default.default(...)

instead of:

dayjs(...)

This results in the runtime failure:

TypeError: 0, dayjs.default.default is not a function

The issue appears to originate from the Datadog Babel plugin or Metro serializer modifying module exports during instrumentation.

Expected Behavior

Modules exporting a default function should remain callable after Datadog instrumentation.

Example expected usage:

import dayjs from "dayjs";

dayjs(value).format();

Current Babel Configuration

module.exports = function (api) {
  api.cache(true);

  return {
    presets: [
      ['babel-preset-expo', { jsxImportSource: 'nativewind' }],
      'nativewind/babel'
    ],
    plugins: [
      [
        'module-resolver',
        {
          root: ['./'],
          alias: {
            '@': './',
            'tailwind.config': './tailwind.config.js',
          },
        },
      ],
      'react-native-worklets/plugin',
      [
        '@datadog/mobile-react-native-babel-plugin',
        {
          sessionReplay: {
            svgTracking: false
          },
          components: {
            useContent: true,
            useNamePrefix: true
          }
        }
      ]
    ]
  };
};

Current Metro Configuration

const { getDefaultConfig } = require("expo/metro-config");
const { withNativeWind } = require("nativewind/metro");
const { getDatadogExpoConfig } = require("@datadog/mobile-react-native/metro");

const datadogConfig = getDatadogExpoConfig(__dirname);

module.exports = withNativeWind(datadogConfig, {
  input: "./global.css",
});

Datadog Setup

const config = new DatadogProviderConfiguration(
  process.env.EXPO_PUBLIC_DATADOG_CLIENT_TOKEN!,
  process.env.EXPO_PUBLIC_DATADOG_ENV!,
  TrackingConsent.GRANTED,
  {
    site: "EU1",
    uploadFrequency: UploadFrequency.FREQUENT,
    batchSize: BatchSize.SMALL,
    verbosity: SdkVerbosity.DEBUG,
    rumConfiguration: {
      applicationId: process.env.EXPO_PUBLIC_DATADOG_APPLICATION_ID!,
      trackInteractions: true,
      trackResources: true,
      trackErrors: true,
      longTaskThresholdMs: 100,
      nativeCrashReportEnabled: true,
      sessionSampleRate: 100
    },
    logsConfiguration: {},
    traceConfiguration: {}
  }
)

Used through:

<DatadogProvider configuration={config}>

Notes

• Only one version of dayjs exists in the dependency tree.
• The issue disappears if the Datadog Babel plugin or Metro integration is removed.
• The problem appears related to how the Datadog instrumentation wraps modules exporting default functions.

Request

Guidance on preventing module export rewriting that produces default.default during Datadog instrumentation in Expo environments.

[cdn34dd]

Hey @sabreu-teknorix , I've tried to reproduce the issue on an sample expo 54 app, but was unsuccessful. It have something to do with your setup in specific, since you're using other plugins/presets like nativeWind. So if you could provide a sample app where the issue is occurring it would greatly help with the debugging process.