unicorn/filename-case

When userProfile.js, UserProfile.js and user-profile.js are all possible, you need to look up the spelling for every import. Capitals are also easy to get wrong without noticing. import "./userprofile.js" finds userProfile.js on macOS and Windows, where the file system usually ignores case, and fails on Linux. By default this rule requires kebab-case.

Only the file name is checked, not its directories. The extension, underscores at the start and the end of the name, index files and files that start with a dot aren't checked.

Configure

Off by default. To turn it on:

[lint.rules]
"unicorn/filename-case" = "error" # or "warn"

Every option, set to its default. The ones that are commented out are unset by default.

[lint.rules]
"unicorn/filename-case" = ["error", {
  case = "kebabCase",
  # cases = <value>,
  ignore = [], # list of strings
  multipleFileExtensions = true,
}]

Examples

Reported:

export function userProfile() {}

export function userProfile() {}

Not reported:

export function userProfile() {}

export function userProfile() {}

Options

Option	Default	What it does
case	"kebabCase"	The one style to allow: "camelCase", "kebabCase", "snakeCase", "pascalCase", "lowercase" or "screamingSnakeCase".
cases		Allow several styles: an object with the names above as keys and true as values. Ignored if case is set.
ignore	[]	Regular expressions, as strings. A file name that matches one of them isn't checked.
multipleFileExtensions	true	Treat everything after the first dot as the extension. With false, only the part after the last dot is the extension.

A project with React components often wants two styles:

export const UserProfile = () => <section />;

export const UserProfile = () => <section />;

ignore matches against the whole file name, including its extension:

export const header = "MIT";

In user-profile.testUtils.js, .testUtils.js counts as the extension by default:

export function render() {}

export function render() {}