eslint-config-pollinate

Purpose

This is a node package that houses ESLint configurations. It enforces a basic standard agreed upon by some of the maintainers of Pollinate’s core JavaScript libraries.

If you’re the maintainer of a project using these standards and wish to change or override these rules, you can:

• Open a pull request to change them for everyone.
• Take advantage of ESLint’s cascading and hierarchy model to override them for a specific directory.
• Use comment-based configurations for a specific file or even lines within the file.

The principle behind these standards is deviations from these standards are OK, but they should be a conscious decision, not a casual oversight.

console and debugger

console and debugger statements are allowed with a warning to keep debugging easy. However, this convenience comes at a cost.

debugger statements will stop JavaScript execution and should never be allowed in production. As such, you should consider how you will prevent them from making their way into production. One possible arrangement is to trigger a build failure on ESLint warnings for anything other than local development.

Verbose, always-on logging can have adverse performance effects in node and clutters shared environments like a browser where more than one script is likely to be running. Ideally, your app or library should use a logging module that’s set up with an inline ESLint rule and toggled on or off depending on an environment variable or query string parameter.

Installation

To install in your project:

$ npm install --save-dev eslint eslint-config-pollinate

You may have multiple environments (e.g. node build scripts and browser code) in the same repo. You can set up multiple .eslintrc.json files in the directories of each of your environments:

.eslintrc.json for generic browser code

{
  "extends": [
    "pollinate/environments/browser"
  ]
}

.eslintrc.json for Vue code (requires eslint-plugin-vue and babel-eslint)

{
  "extends": [
    "pollinate/environments/vue"
  ]
}

.eslintrc.json for node code

{
  "extends": [
    "pollinate/environments/node"
  ]
}

.eslintrc.json for universal (a.k.a. isomorphic) code

{
  "extends": [
    "pollinate/environments/universal"
  ]
}

You may also want to add environments for common libraries and an ESLint plugin for templating languages such as JSX that mix JavaScript with proprietary markup.

Last but not least: set your build up to enforce ESLint. JavaScript developers tend to use a variety of editors set up in a variety of ways. It’s up to you to ensure that a contributor to your project who isn’t running ESLint in their editor won’t run afoul of your project’s rules and trip up the next contributor who is running ESLint in theirs. ESLint has plugins for grunt, gulp and webpack. If you’re rolling your own build from scratch, ESLint’s CLI is pretty straightforward and is also accessible via a JavaScript API.

Automatic fixing

If you want linting errors to be automatically corrected, you have a couple of options:

1. Set your build up to run the --fix option in the ESLint cli.
2. Use a tool like eslint-to-editorconfig to dynamically generate an .editorconfig file.

There is no straightforward way to incorporate either of these options into this package, so they’re both optional and up to you to implement.

Versioning

This package follows semantic versioning (major.minor.patch). In this case:

• A patch change fixes a bug or removes a rule. This should not generate any new linting errors.
• A minor change may add a new rules that may generate some new linting errors, but they should be easily fixed.
• A major change adds significant new rules, renames or restructures existing rules, or upgrades the ESLint dependency to a new major version.