Eslint - SourceType mixture of script and module

Question

We are starting to mix in some es6 modules and eslint justly complains when you use import/export when not using the sourceType: script

Parsing error: 'import' and 'export' may appear only with 'sourceType: module'at line 1 col 1

However if I change sourceType to module then every file that has 'use strict'; at the top gets flagged saying use strict isn't needed in modules.

The modules are my jsx files and my js files are POJ so I need both sourceTypes to be operating.

Any ideas on how to coerce eslint to behave with both modules and scripts? I would like to avoid running two seperate eslintrc files and rule sets just to have one be modules and the other be scripts.

Answer 1

As long as as your scripts have one extension and your modules have a different extension, then you can have two different configs.

// .eslintrc.json
{
    // ...
    // Your normal config goes here
    // ...
}

Lint your normal scripts with eslint ., just like you've been doing. It defaults to sourceType: "script", pulls .eslintrc.json by default, and only lints *.js files by default.

// .eslintrc.modules.json
{
    "extends": "./.eslintrc.json",
    "parserOptions": {
        "sourceType": "module"
    },
    // You can have additional module-specific config here if you want
}

Now you can lint just the modules using eslint --config .eslintrc.modules.json --ext .jsx ., which will pull the modules config, which is just an extension of the normal .eslintrc.json, and it will only lint the *.jsx files.

Answer 2

There's a nicer approach now in eslint 4.1.0+:

module.exports = {
  overrides: [
    {
      files: [ "rollup.config.js" ],
      parserOptions: { sourceType: "module" },
    }
  ]
};

You can also change rules or whatever you want, per-glob, in the overrides section.

Answer 3

I've created the main file in the root folder with option sourceType: script. When in a folder ./front file .eslintrc.json:

{
    "extends": "../.eslintrc.json",
    "parserOptions": {
        "sourceType": "module"
    }
}