Linter

Development

Create a ./test.ts and then

just watch "run -p oxc_cli --bin oxlint -- test.ts"

Or test and filter against the rule:

just watch "test -p oxc_linter -- rule-name"

Snapshot Testing

cargo insta is used for snapshot testing.

After running cargo test -p oxc_linter and the line Tester::new(RULE::NAME, pass, fail).test_and_snapshot() is called, a new rule.snap.new file will be generated.

Use cargo insta accept to accept all snapshot changes.

Rule generation

Create a new lint rule by providing the ESLint name

just new-rule name

Then add the rule to crates/oxc_linter/src/rules.rs:

1. Add to mod
2. Add to oxc_macros::declare_all_lint_rules at the bottom of the file

For other plugins, there are also:

just new-jest-rule name
just new-ts-rule name
just new-unicorn-rule name
just new-react-rule name
just new-jsx-a11y-rule name
just new-oxc-rule name
just new-deepscan-rule name
just new-nextjs-rule name

Rule Category

• correctness - code that is outright wrong or useless
• suspicious - code that is most likely wrong or useless
• pedantic - lints which are rather strict or have occasional false positives
• perf - code that can be written to run faster
• style - code that should be written in a more idiomatic way
• restriction - lints should be considered on a case-by-case basis before enabling.
• nursery - new lints that are still under development

General Advice

Pin point the error message to the shortest code span

We want the user to focus on the problematic code rather than deciphering the error message to identify which part of the code is erroneous.