Could not find plugin “proposal-numeric-separator”

Question

How to fix Could not find plugin \"proposal-numeric-separator\", I get this error when I try to build my React application, I have not ejected the application y

Answer 1

Why this problem happened?:

It's an issue of conflicts between internal packages used by babel.

Adding a new plugin to @babel/compat-data breaks old @babel/preset-env versions. This is because preset-env iterates over compat-data's plugins, and throws if the plugin isn't defined in preset-env's available-plugins.js file.

This is the merge that fixed the issue: https://github.com/babel/babel/pull/11201/files/a88a00750c61ff89f1622d408d67108719f21ecd

Solution:

• Delete package-lock.json or yarn.lock
• Delete node_modules folder
• In package.jon I have adjusted the version numbers of these packages to:

    ...
    "devDependencies": {
        "@babel/compat-data": "^7.8.0",
        "@babel/preset-env": "^7.8.0",
        "babel-loader": "^8.1.0",
        ...
    },
    ...
    "resolutions": {
        "@babel/preset-env": "^7.8.0"
    }

• Run npm install
• Run npm run build