oxc-project/oxc · warning · OxcDiagnostic

No spaces inside empty pair of braces allowed

Error message

No spaces inside empty pair of braces allowed

What it means

Diagnostic from oxlint's `unicorn/empty-brace-spaces` rule. It reports braces that are empty but contain whitespace or newlines: empty object literals (`{ }`), empty function bodies, empty class bodies (`class A {\n}`), empty block statements, and empty `static {}` blocks. Braces containing comments between them are respected and not flagged. The autofix rewrites the whole span to `{}` (or `static {}` for static blocks).

Source

Thrown at crates/oxc_linter/src/rules/unicorn/empty_brace_spaces.rs:9

use oxc_ast::AstKind;
use oxc_diagnostics::OxcDiagnostic;
use oxc_macros::declare_oxc_lint;
use oxc_span::Span;

use crate::{AstNode, context::LintContext, rule::Rule};

fn empty_brace_spaces_diagnostic(span: Span) -> OxcDiagnostic {
    OxcDiagnostic::warn("No spaces inside empty pair of braces allowed")
        .with_help("There should be no spaces or new lines inside a pair of empty braces as it affects the overall readability of the code.")
        .with_label(span)
}

#[derive(Debug, Default, Clone)]
pub struct EmptyBraceSpaces;

declare_oxc_lint!(
    /// ### What it does
    ///
    /// Removes the extra spaces or new line characters inside a pair of braces
    /// that does not contain additional code. This ensures that braces are clean
    /// and do not contain unnecessary spaces or newlines.
    ///
    /// ### Why is this bad?
    ///
    /// Extra spaces inside braces can negatively impact the readability of the code.
    /// Keeping braces clean and free of unnecessary characters improves consistency and

View on GitHub (pinned to e1e7af627c)

Solutions

1. Run `oxlint --fix` (or your formatter) to collapse `{ }` to `{}`.
2. Enable format-on-save so brace layout is owned by the formatter, not hand edits.
3. If a comment inside the braces is intentional, the rule already skips it — keep the comment and no diagnostic fires.

Example fix

// before
const a = {  };
class A {
}
// after
const a = {};
class A {}

When it happens

Trigger: Any empty brace pair whose span is longer than two characters — `const a = { };`, `class A {\n}`, `function f() { }`, `if (x) { }`, `static { }` — with no comments inside.

Common situations: Formatter divergence (Prettier not run on the file), code pasted from editors that expand braces, and CI lint runs on manually edited files where format-on-save was off.

Related errors

• Prefer `{} {}` over `{} {}` to check {}.
• Invalid escape sequence in template literal.
• Use uppercase characters for the value of the escape sequenc
• The {expr_type} is useless
• Don't use a zero fraction in the number.

AI-assisted analysis of oxc-project/oxc@e1e7af627c (2026-08-20). Data as JSON: /api/errors/685a78fe2548068b. Report an issue: GitHub.