sindresorhus/eslint-plugin-unicorn

Rule proposal: `no-useless-else`

Open

#987 opened on Jan 2, 2021

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 (3 comments) (8 reactions) (0 assignees)JavaScript (5,022 stars) (468 forks)user submission
help wantednew rule

Description

If the body of if contains one of these keywords, the else is moot:

  • throw
  • break
  • continue
  • return

This slightly overlaps with https://eslint.org/docs/rules/no-else-return

This was inspired by https://github.com/eslint/eslint/issues/13067.

This could be auto-fixed, but we should take care to properly move any comments.

Fail

if (foo) {
	throw new Error();
} else {
	console.log('🦄');
}

Pass

if (foo) {
	throw new Error();
} 

console.log('🦄');

Contributor guide

Tech stack
javascriptnodejs
Domain
developer experiencetooling
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.
1-2 days
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.
mostly clear
Prerequisites
ESLint rule development experienceAST knowledge
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
30
Research direction
Examine the existing `no else return` rule in ESLint core for reference. Study the AST representation of if else statements with throw/break/continue/return. Implement the rule in the plugin, ensuring comments in the else block are preserved or moved appropriately. Write unit tests for all cases. Consider opening a draft PR for early feedback.