oxc-project/oxc · error · OxcDiagnostic

Assign arrow function to a variable before exporting as modu

Error message

Assign arrow function to a variable before exporting as module default

What it means

Fires from import/no-anonymous-default-export when the default export is an arrow function expression and allowArrowFunction is false. Unlike the anonymous function/class cases, this message is actionable advice: assign the arrow function to a named variable first.

Source

Thrown at crates/oxc_linter/src/rules/import/no_anonymous_default_export.rs:157

                ctx.diagnostic(no_anonymous_default_export_diagnostic(
                    export_decl.span,
                    "Unexpected default export of anonymous function",
                ));
            }
            ExportDefaultDeclarationKind::ClassDeclaration(class_decl)
                if !self.allow_anonymous_class && class_decl.id.is_none() =>
            {
                ctx.diagnostic(no_anonymous_default_export_diagnostic(
                    export_decl.span,
                    "Unexpected default export of anonymous class",
                ));
            }
            ExportDefaultDeclarationKind::ArrowFunctionExpression(_)
                if !self.allow_arrow_function =>
            {
                ctx.diagnostic(no_anonymous_default_export_diagnostic(
                    export_decl.span,
                    "Assign arrow function to a variable before exporting as module default",
                ));
            }
            ExportDefaultDeclarationKind::ObjectExpression(_) if !self.allow_object => {
                ctx.diagnostic(no_anonymous_default_export_diagnostic(
                    export_decl.span,
                    "Assign object to a variable before exporting as module default",
                ));
            }
            ExportDefaultDeclarationKind::CallExpression(_) if !self.allow_call_expression => {
                ctx.diagnostic(no_anonymous_default_export_diagnostic(
                    export_decl.span,
                    "Assign call result to a variable before exporting as module default",
                ));
            }
            ExportDefaultDeclarationKind::NewExpression(_) if !self.allow_new => {
                ctx.diagnostic(no_anonymous_default_export_diagnostic(
                    export_decl.span,
                    "Assign instance to a variable before exporting as module default",

View on GitHub (pinned to e1e7af627c)

Solutions

  1. Assign the arrow function to a named const, then `export default` that variable
  2. Enable `allowArrowFunction` to permit arrow default exports
Defensive patterns

Strategy: validation

When it happens

Trigger: Thrown at crates/oxc_linter/src/rules/import/no_anonymous_default_export.rs:157 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/2c40dd69c1b4cff8. Report an issue: GitHub.