Metro Has Encountered an error: Cannot read properties of undefined(reading 'transformfile'). ERROR
Metro Has Encountered an error: Cannot read properties of undefined(reading 'transformfile'). ERROR
Matthew C.
—The Problem
When bundling your React Native JavaScript code, you may encounter the following error:
Metro Has Encountered an error: Cannot read properties of undefined (reading 'transformfile'): node_modules/metro/src/Bundler.js (48:30)
You may also get the related error: error:0308010C:digital envelope routines::unsupported.
The Solution
The error occurs when your version of React Native uses Metro version 0.66.2 or lower, which causes compatibility issues with Node version 17+.
Upgrade your React Native to version 0.68, which uses Metro version 0.67+.
If you can’t upgrade React Native, you can use the --openssl-legacy-provider command-line option, added to Node version 17, to allow you to use legacy algorithms. This should be used as a temporary workaround for the error.
Alternatively, you can downgrade Node to version 16 or lower.
Note
Metro is a JavaScript bundler built and optimized for React Native. The Expo CLI uses Metro during npx expo start and npx expo export to bundle your JavaScript code.
Prior to version 0.67.0, Metro used the cryptographic hashing algorithm "md4"from the Node crypto library.When Node version 17 updated OpenSSL to OpenSSL 3.0, several cryptographic algorithms were deprecated, including "md4".
Because OpenSSL version 3+ classifies "md4" as an OpenSSL legacy algorithm, Node version 17+ is incompatible with any version of Metro that uses the "md4" hash function.
Metro version 0.67.0 resolved this issue by replacing "md4" with the more secure "md5" cryptographic hash function.
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