sindresorhus/eslint-plugin-unicorn

Rule proposal: `better-boolean-var-name`

Closed

#2,441 opened on Sep 1, 2024

View on GitHubContributor guide
 (7 comments) (1 reaction) (0 assignees)JavaScript (468 forks)user submission
help wantednew ruletypes

Repository metrics

Stars
 (5,022 stars)
PR merge metrics
 (Avg merge 1d 16h) (399 merged PRs in 30d)

Description

Description

There are many irregular variable declarations in some Boolean variable declarations.

For example

const showingModal = false

This value is obviously a Boolean value, but it cannot be seen from the variable.

A better variable name can improve code readability

Boolean variables should start with 'is', 'was', 'has', 'can', 'should', etc.

Fail

const showingModal = false

const greatThen = a > b

const completed = progress === 100

const setProperty = key in object

const stringType = typeof input === 'string'

// ...

Pass

const isShowingModal = false

const isGreatThen = a > b

const isCompleted = progress === 100

const hasSetProperty = key in object

const isStringType = typeof input === 'string'

Proposed rule name

better-boolean-var-declaration

Additional Info

This rule has been implemented in my company project, it can't autofix, but it can provide suggestions. I think it is useful

If this is acceptable, I'd be happy to PR

https://github.com/user-attachments/assets/c6bbccea-5efc-4fc5-8beb-3fb2fb0e1bd9

Contributor guide

Research direction
Study existing ESLint rules in this plugin for patterns, especially those that detect variable declarations. Look for AST selectors for variable declarators. Write tests for failing and passing cases. The rule should check boolean variable names and suggest prefixes like 'is', 'was', etc. No autofix, only suggestions. Use ESLint's suggest API.
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.
2
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.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
ESLint plugin development
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60