Microbundle: (babel plugin) TypeError: path.isClassPrivateMethod is not a function

[FezVrasta]

As soon I run microbundle build I get this error.

TypeError: path.isClassPrivateMethod is not a function
    at verifyUsedFeatures (node_modules/microbundle/node_modules/@babel/helper-create-class-features-plugin/lib/features.js:46:12)

I'm running it from a sub-folder of a monorepo, I'm not sure if that may be related. The monorepo root uses react-styleguidist and create-react-app 2.0

[developit]

I believe this is a babel versioning issue. I was able to resolve it when I encountered it locally by wiping node_modules and reinstalling.

[developit]

Hi @FezVrasta - can you paste the output of this?

npm ls @babel/plugin-proposal-class-properties

[FezVrasta]

Thanks for the reply, I deleted all the node_modules and reinstalled everything but I still get the same error.

Here's the output of npm ls:

❯ npm ls @babel/plugin-proposal-class-properties
[email protected] ui/packages/emotion-button
└── (empty)

If I install microbundle on the root directory of the monorepo it works just fine. (I need to call it with ../../node_modules/.bin/microbundle)

It also works fine if I install it on the root, and on the packages/emotion-button folder 🤷‍♂️ (in this case I can just use microbundle)

[ForsakenHarmony]

it might be conflicting with another version of the same package from another dependency

have you tried installing with yarn? (had this problem before and npm handles it badly in some cases)

[FezVrasta]

I'm using Yarn already, microbundle seems to be resolved to a single version (0.8.3) according to the yarn.lock file

[ForsakenHarmony]

I don't mean microbunle, the babel plugin might be

[ForsakenHarmony]

also did you run npm ls after installing it? because it won't output anything if you delete node_modules first

[FezVrasta]

Yes I ran it after installing.

@babel/plugin-proposal-class-properties (according to yarn.lock) is required only by [email protected] and [email protected], both of them require the version 7.1.0

[paulmelnikow]

This error also occurs in a non-microbundle project when updating @babel/plugin-proposal-class-properties to 7.2.0: badges/shields#2449.

[paulmelnikow]

And… looks like it's been fixed in 7.2.1: babel/babel#9120 badges/shields#2455

[developit]

Fixed in Babel.