BABEL_TRANSFORM_ERROR - babel traverse context - cannot read property "removeBinding" of null

Bug Report

EDIT by @nicolo-ribaudo

You can workaround this bug by making sure that @babel/core uses an older @babel/traverse version. If you are using yarn you can specify "@babel/traverse": "7.12.0" in resolutions, otherwise you can try downgrading it as described by https://github.com/babel/babel/issues/12383#issuecomment-732049261.

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https://github.com/babel/babel/pull/12331 after this pr

“This is technically a breaking change (we are changing the default value of a parameter in the public API), but I couldn’t find anyone online using that parameter and I’m not sure why anyway would not wont it to use the correct context.”

is there anyone that do code review, here @babel ?

What do you think about semver?

[nicolo-ribaudo]

I’ll open a PR today, hoping for a patch release today.

@w3nda You can try https://github.com/babel/babel/issues/12383#issuecomment-732049261, which is a generic workaround and not specific to babel-minify.

[ehoogeveen]

I think babel-plugin-minify-simplify is triggering this error (whether the fault is with the plugin or babel itself I don’t know). It can be seen when minifying bowser v1.9.4 for example.

To reproduce:

1. Using node.js LTS v14.15.1 with npm version 6.14.8, set up a clean node project.
2. Run npm install --save-dev @babel/cli @babel/core babel-preset-minify bowser@1.9.4
3. Run npx babel --presets=babel-preset-minify node_modules/bowser/bowser.js