What is the correct location to define the "env" setting in the eslint.config.js file?

Question

What is the correct location to define the "env" setting in the eslint.config.js file?

In 2022, ESLint rolled out a new configuration system called the "flat config" here.

Check out the documentation for the new "flat config". | Old configuration system documentation here.

The "flat config" documentation shows that the `eslint.config.js` file doesn't have an `env` key to specify the environment (e.g., "node" or "browser"), unlike the old system using `.eslintrc.js` or `.eslintrc.json`.

If you don't specify the `env` property as `node`, you'd need to manually add all node global variables like this:

`eslint.config.js`:

module.exports [
    {
        files: ["**/*.js"],
        languageOptions: {
            globals: {
                console: "writable",
                __dirname: "readable",
                __filename: "readable",
                process: "readable",
                < … more global variables here … >
            }
        },
        rules: {
            // your rules here
        }
    }
]

Am I overlooking something here?

javascript node.js npm eslint eslint-flat-config

Answer 1

Answer №1

Their blog contains more detailed information on the "env" topic, which required a significant amount of time to locate...

https://eslint.org/blog/2022/08/new-config-system-part-2/#reimagined-language-options

In the flat config, all keys related to JavaScript evaluation [including env] have been moved into a new top-level key called languageOptions.

https://eslint.org/blog/2022/08/new-config-system-part-2/#goodbye-environments%2C-hello-globals

It doesn't seem logical for ESLint to handle this in its core functionality, so the responsibility is being returned to users. [Yes, it does, as evident from this stack overflow thread]

They then provide a basic example:

export default [
    {
        files: ["**/*.js"],
        languageOptions: {
            globals: {
                ...globals.browser,
                myCustomGlobal: "readonly"
            }
        }
    }
];

I believe we may simply require:

    {
        files: ["**/*.js"],
        languageOptions: {
            globals: {
                ...globals.node
            }
       }
    }

This solution worked for me (I also included parser: babelParser within languageOptions)

In my opinion, ESLint is complicating things by not providing a clear migration path and seems to be setting themselves up for trouble if they release ESLint 9.0 without eslintrc support and take a "not-my-problem" stance towards documenting how to transition from "env": { "node": true }. They haven't even properly documented the plugins formatting, which involves a "key-value" mapping strings to plugin objects. For instance, { "html": yourHtmlPluginImport }

Answer 2

Their blog contains more detailed information on the "env" topic, which required a significant amount of time to locate...

https://eslint.org/blog/2022/08/new-config-system-part-2/#reimagined-language-options

In the flat config, all keys related to JavaScript evaluation [including env] have been moved into a new top-level key called languageOptions.

https://eslint.org/blog/2022/08/new-config-system-part-2/#goodbye-environments%2C-hello-globals

It doesn't seem logical for ESLint to handle this in its core functionality, so the responsibility is being returned to users. [Yes, it does, as evident from this stack overflow thread]

They then provide a basic example:

export default [
    {
        files: ["**/*.js"],
        languageOptions: {
            globals: {
                ...globals.browser,
                myCustomGlobal: "readonly"
            }
        }
    }
];

I believe we may simply require:

    {
        files: ["**/*.js"],
        languageOptions: {
            globals: {
                ...globals.node
            }
       }
    }

This solution worked for me (I also included parser: babelParser within languageOptions)

In my opinion, ESLint is complicating things by not providing a clear migration path and seems to be setting themselves up for trouble if they release ESLint 9.0 without eslintrc support and take a "not-my-problem" stance towards documenting how to transition from "env": { "node": true }. They haven't even properly documented the plugins formatting, which involves a "key-value" mapping strings to plugin objects. For instance, { "html": yourHtmlPluginImport }

Answer 3

Answer №2

The solution can be found in the migration guide, as highlighted below:

When working with eslintrc files, language options like env, globals, and parserOptions are configured differently. The env property is used to group global variables for specific runtimes (e.g. browser JavaScript uses document and window; Node.js uses process and require).

In flat config files, globals and parserOptions are combined under the languageOptions key, while the env property is no longer present. Global variables for different runtimes are now imported from the globals npm package and added to the globals property. You can also use the spread operator (...) to import multiple globals at once.

Reference the globals npm package and follow these steps:

import globals from "globals";

const customGlobals = {
  TomSelect: "readable",
}

export default [{
  languageOptions: {
      globals: {
        ...customGlobals,
        ...globals.browser,
        ...globals.jquery,
        ...globals.node,
      },
    }
  }
}];

Answer 4

The solution can be found in the migration guide, as highlighted below:

When working with eslintrc files, language options like env, globals, and parserOptions are configured differently. The env property is used to group global variables for specific runtimes (e.g. browser JavaScript uses document and window; Node.js uses process and require).

In flat config files, globals and parserOptions are combined under the languageOptions key, while the env property is no longer present. Global variables for different runtimes are now imported from the globals npm package and added to the globals property. You can also use the spread operator (...) to import multiple globals at once.

Reference the globals npm package and follow these steps:

import globals from "globals";

const customGlobals = {
  TomSelect: "readable",
}

export default [{
  languageOptions: {
      globals: {
        ...customGlobals,
        ...globals.browser,
        ...globals.jquery,
        ...globals.node,
      },
    }
  }
}];

What is the correct location to define the "env" setting in the eslint.config.js file?

Answer №1

Answer №2

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