sindresorhus/eslint-plugin-unicorn

Rule proposal: Require extension for relative imports and re-exports

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#1,194 opened on Apr 20, 2021

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help wantednew rule

Description

It would enforce using a .js extension for relative imports if it doesn't already have an extension.

We cannot auto-fix as we cannot know whether import foo from './foo'; refers to a file or directory.

This even applies to TypeScript, where you still need the .js extension even if you import other .ts files.

There's already the import/extensions rule, but that project is not very actively maintained, very buggy, and also it doesn't let us use .js extension for TypeScript files. I think it's worth adding this simple rule here.

This rule will not do anything about require() statements.

Fail

import foo from './foo';

export foo from './foo';

await import('./foo');

Pass

import foo from './foo.js';

export foo from './foo.js';

await import('./foo.js');

import foo from './foo.vue';

Contributor guide

Tech stack
javascripttypescript
Domain
tooling
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
Understanding of ESLint pluginsJavaScript module systemAST concepts
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
65
Research direction
Review existing rules in the repository (e.g., lib/rules) to understand the pattern for implementing a new rule. Examine the test structure in test/rules. Note that the issue discusses the need for a rule that enforces .js extension for relative imports, similar to import/extensions but with better support for TypeScript. Check the comments for any additional requirements or discussions. There is no linked PR, so implementation can start from scratch.