sindresorhus/eslint-plugin-unicorn

Rule proposal: Have `prefer-spread` handle `for..of`

Closed

#1,713 opened on Feb 3, 2022

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 (3 comments) (1 reaction) (0 assignees)JavaScript (468 forks)user submission
enhancementhelp wanted

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Description

Description

Often no-for-loop results in something that is a simple spread, which prefer-spread should handle

This works for both arrays and iterators.

Fail

const result = []
for (const element of array) {
  result.push(element)
}

const result = []
for (const [index, element] of array.entries()) {
  result[index] = element
}

Pass

const result = [...array]

Contributor guide

Research direction
Review the existing `prefer spread` rule (https://github.com/sindresorhus/eslint plugin unicorn/blob/main/rules/prefer spread.md) and `no for loop` rule (https://github.com/sindresorhus/eslint plugin unicorn/blob/main/rules/no for loop.md). Investigate how `for..of` loops can be detected and whether the suggested pattern (converting to spread) is always safe. Check existing tests and comments in the issue for any edge cases or maintainer feedback.
Tech stack
javascript
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.
Fresh
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Mostly clear
Prerequisites
basic knowledge of ESLint rulesunderstanding of for..of loopsfamiliarity with JavaScript spread syntax
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
40