sindresorhus/eslint-plugin-unicorn

Rule proposal: `no-unnecessary-splice`

Open

#2,359 opened on May 16, 2024

View on GitHub
 (8 comments) (6 reactions) (0 assignees)JavaScript (5,022 stars) (468 forks)user submission
help wantednew rule

Description

Description

Saw splice being used instead of push/pop/shift/unshift in some projects. AFAIK it brings no performance gain and is harder to read/understand than the latter ones.

Basically bans:

  • array.splice(index, 0) (can be removed as no-op)
  • array.splice(0, 1) (as substitutable by array.shift())
  • array.splice(0, 0, element) (as substitutable by array.unshift(element) - for 1 or more elements)
  • array.splice(array.length - 1, 1) (as substitutable by array.pop())
  • array.splice(array.length, 0, element) (as substitutable by array.push(element) - for 1 or more elements)

Should be easy to implement auto-fixer for those replacements.

Fail

array.splice(start, 0)

array.splice(0, 1)

array.splice(array.length, 0, element)

Pass

array.shift()

array.push(element)

Proposed rule name

no-unnecessary-splice

Additional Info

Happy to work on this once accepted (already have a stub).

This would make #2165 not needed any more

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.
half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
Basic knowledge of ESLint rulesUnderstanding of ASTJavaScript proficiency
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
55
Research direction
Study the existing ESLint rules in `eslint plugin unicorn` (e.g., `rules/` directory) to understand the pattern. The author mentions having a stub; check comments for any shared code. The rule should detect `array.splice(0,1)`, `array.splice(0,0,element)`, etc., and provide auto fixes. Review issue #2165 for related context.