"plugin:node/recommended" generates: Parsing error: 'import' and 'export' may appear only with 'sourceType: module'

There was another issue like this, seen here: https://github.com/mysticatea/eslint-plugin-node/issues/135 but it was closed. But I felt it was warranted to open a new issue since this seems to be a problem with this plugin, which goes against the answer in that issue.

I have the following configuration:

  "extends": [
    "airbnb-base",
    "plugin:node/recommended",
    "plugin:jest/recommended",
    "plugin:jest/style",
    "plugin:jsdoc/recommended",
    "plugin:prettier/recommended"
  ],

If I remove "plugin:node/recommended",, the error Parsing error: 'import' and 'export' may appear only with 'sourceType: module' goes away. So it is this plugin generating this error somehow.

The reason why I get this is because I use commonjs (i.e. require()) instead of ecmascript modules (i.e. import) in my code. But for Jest test cases, I use import because those are transformed by babel anyway. So I get the error in those files only.

I can work around this by setting an overrides to use another sourceType like so:

  "overrides": [{
    "files": ["path/to/some/file.js", "path/to/some/folder/**.js"],
    "parserOptions": {
      "sourceType": "module"
    }
  }]

But the question is, why is this error generated at all due to the inclusion of "plugin:node/recommended",?

[mysticatea]

Your workaround (overrides parserOptions.sourceType) is right.

But it may be nice to use plugin:node/recommended-module instead.

  "overrides": [{
    "files": ["path/to/some/file.js", "path/to/some/folder/**.js"],
    "extends": "plugin:node/recommended-module"
  }]

• It configures the rules of this plugin for ES modules. For example, it reports some global variables that we cannot use in ES modules, and tweaks the node/no-unsupported-features/es-syntax rule to ignore ES modules syntax.

Or, if you are sure that all *.js files are ES modules, you can use plugin:node/recommended-module instead of plugin:node/recommended:

  "extends": [
    "airbnb-base",
    "plugin:node/recommended-module",
    "plugin:jest/recommended",
    "plugin:jest/style",
    "plugin:jsdoc/recommended",
    "plugin:prettier/recommended"
  ],

[ljharb]

I’d suggest using “unflagged” and not “not experimental”, personally. It’s fully usable with no experimental warning in node v12.17.