oxc-project/oxc · warning

Should not have leading or trailing spaces

Error message

Should not have leading or trailing spaces

What it means

Diagnostic from the shared jest/vitest `valid-title` rule (accidental_space_diagnostic). It fires when a test title has leading or trailing whitespace — `' saves a user '` — which is invisible in reports but breaks exact-name filtering and looks like a typo.

Source

Thrown at crates/oxc_linter/src/rules/shared/jest_vitest/valid_title.rs:42

    OxcDiagnostic::warn("Title must be a string")
        .with_help("Replace your title with a string")
        .with_label(span)
}

fn empty_title_diagnostic(span: Span) -> OxcDiagnostic {
    OxcDiagnostic::warn("Should not have an empty title")
        .with_help("Write a meaningful title for your test")
        .with_label(span)
}

fn duplicate_prefix_diagnostic(span: Span) -> OxcDiagnostic {
    OxcDiagnostic::warn("Should not have duplicate prefix")
        .with_help("The function name already has the prefix, try to remove the duplicate prefix")
        .with_label(span)
}

fn accidental_space_diagnostic(span: Span) -> OxcDiagnostic {
    OxcDiagnostic::warn("Should not have leading or trailing spaces")
        .with_help("Remove the leading or trailing spaces")
        .with_label(span)
}

fn disallowed_word_diagnostic(word: &str, span: Span) -> OxcDiagnostic {
    OxcDiagnostic::warn(format!("{word} is not allowed in test title"))
        .with_help("It is included in the `disallowedWords` of your config file, try to remove it from your title")
        .with_label(span)
}

pub fn must_match_diagnostic(message: &str, span: Span) -> OxcDiagnostic {
    OxcDiagnostic::warn(message.to_string())
        .with_help("Make sure the title matches the `mustMatch` of your config file")
        .with_label(span)
}

pub fn must_not_match_diagnostic(message: &str, span: Span) -> OxcDiagnostic {
    OxcDiagnostic::warn(message.to_string())

View on GitHub (pinned to e1e7af627c)

Solutions

1. Trim the title: `it('saves a user', fn)`.
2. When composing titles programmatically, trim the result: `\`${base} ${case}\`.trim()`.
3. Enable editor trim-on-save / whitespace visualization to catch stray spaces at authoring time.

Example fix

// before
it('  shows the dashboard  ', () => { /* ... */ });

// after
it('shows the dashboard', () => { /* ... */ });

const re = /\b(it|test|describe)(\.(skip|only|each))?\s*\(\s*(['"])[ \t]+|(['"])[ \t]+\s*,/;
if (re.test(src)) { console.error('title has leading/trailing spaces'); process.exitCode = 1; }

When it happens

Trigger: String-literal titles whose trimmed value differs from the original: `it(' does nothing ', fn)`, `describe(' repo ', () => {})`, usually from sloppy paste or template building with stray spaces.

Common situations: Concatenated titles (`' ' + name`), copy-paste with trailing spaces editors don't render, and generator templates with padded placeholders.

Related errors

• Title must be a string
• Should not have an empty title
• Should not have duplicate prefix
• {word} is not allowed in test title
• {un_prefixed_name} should match {raw_pattern}

AI-assisted analysis of oxc-project/oxc@e1e7af627c (2026-08-20). Data as JSON: /api/errors/7049c141fc1fb08e. Report an issue: GitHub.