oxc-project/oxc · error · OxcDiagnostic

Only files containing JSX may use the extension '.{ext}'

Error message

Only files containing JSX may use the extension '.{ext}'

What it means

Raised by react/jsx_filename_extension when configured with `allowAsRequired` and the file uses a JSX-permitting extension (like .jsx/.tsx) without containing any JSX. At the throw site the extension claims JSX content that is not there, which misleads module consumers and tooling about the file's contents. extension_only_for_jsx_diagnostic is produced by run_once() when the filename extension is allowed only for JSX files but no JSX element exists in the module.

Source

Thrown at crates/oxc_linter/src/rules/react/jsx_filename_extension.rs:30

use oxc_str::CompactStr;

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

fn no_jsx_with_filename_extension_diagnostic(
    ext: &str,
    span: Span,
    allowed_extensions: &[CompactStr],
) -> OxcDiagnostic {
    OxcDiagnostic::warn(format!("JSX not allowed in files with extension '.{ext}'"))
        .with_help(format!(
            "Rename the file to use an allowed extension: {}",
            allowed_extensions.iter().map(|e| format!(".{e}")).join(", ")
        ))
        .with_label(span)
}

fn extension_only_for_jsx_diagnostic(ext: &str, span: Span) -> OxcDiagnostic {
    OxcDiagnostic::warn(format!("Only files containing JSX may use the extension '.{ext}'"))
        .with_help("Rename the file with a good extension.")
        .with_label(span)
}

#[derive(Debug, Default, Clone, JsonSchema, Deserialize, Serialize)]
#[serde(rename_all = "kebab-case")]
enum JsxFilenameExtensionAllowMode {
    /// Always allow a JSX filename extension.
    #[default]
    Always,
    /// Only allow JSX filename extension for files that contain JSX syntax.
    AsNeeded,
}

impl JsxFilenameExtensionAllowMode {
    pub fn from(raw: &str) -> Self {
        match raw {
            "as-needed" => Self::AsNeeded,

View on GitHub (pinned to e1e7af627c)

Solutions

1. Rename the file to .js or .ts if it contains no JSX.
2. Add JSX if the file was intended to contain markup.

When it happens

Trigger: Thrown at crates/oxc_linter/src/rules/react/jsx_filename_extension.rs:30 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of oxc-project/oxc@e1e7af627c (2026-08-20). Data as JSON: /api/errors/fad1ff9474e12a36. Report an issue: GitHub.