Creating different eslint rules for local development

Question

Here's a motivating example: I am developing some code and want to figure out what's going wrong, so I have

function foo() {
    console.log("Look its 2016 and I'm still printf debugging");
}

Except... our build process runs esLint as part of the build system and by-design prevents even running the rest of the build pipeline if esLint fails. error Unexpected console statement no-console

What I effectively want is to set up a dev environment where certain rules are turned off (or converted to warnings), and then a production environment with the strict rules turned on. And I want to be able to easily toggle that locally so I can verify my code works before submitting it to a CI server.

I can't find any relevant code snippets to make this happen, which makes me sad. My build environment is just npm scripts (just using the esLint CLI + package.json), but I would be happy to port a solution from another build environment.

Right now, I'm left with either // eslint-disable-line or locally modifying an .eslintrc file and praying I never accidentally check that in by accident. There must be a better way.

Answer 1

Branch your rules by NODE_ENV

You can use .js version of eslint config (eslintrc.js) and branch your rules based on NODE_ENV variable.

In eslintrc.js:

rules: {
 
  'no-console':
    process.env.NODE_ENV === 'production'
      ? 'error'
      : 'warn'

}

Scripts in package.json:

"scripts": {
  "lint": "eslint",
  "lint:prod": "NODE_ENV=production eslint"
}

You will use one version of the rule and your CI the other (assuming NODE_ENV on your CI is set to production).

Answer 2

From a related thread on github: https://github.com/eslint/eslint/issues/6460#issuecomment-226967834

It looks like what I am going to do is make a dev.eslintrc or similar and have that extend the main .eslintrc. And then I can use command line args to switch between the two rulesets as needed.