oxc-project/oxc · error · OxcDiagnostic

Do not export `then`.

Error message

Do not export `then`.

What it means

Raised by unicorn/no-thenable (export helper) when a module exports a binding named `then`. ES modules treat a `then` export specially during dynamic import (`import()` unwraps it), which breaks expectations; the faulting input is the `then` export at the labeled span.

Source

Thrown at crates/oxc_linter/src/rules/unicorn/no_thenable.rs:21

    ast::{
        Argument, ArrayExpressionElement, AssignmentExpression, AssignmentTarget, BindingPattern,
        CallExpression, Declaration, Expression, ObjectPropertyKind, PropertyKey, match_expression,
    },
};
use oxc_diagnostics::OxcDiagnostic;
use oxc_macros::declare_oxc_lint;
use oxc_span::{GetSpan, Span};

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

fn object(span: Span) -> OxcDiagnostic {
    OxcDiagnostic::warn("Do not add `then` to an object.")
        .with_help("If an object is defined as 'thenable', once it's accidentally used in an await expression, it may cause problems")
        .with_label(span)
}

fn export(span: Span) -> OxcDiagnostic {
    OxcDiagnostic::warn("Do not export `then`.")
        .with_help("If an object is defined as 'thenable', once it's accidentally used in an await expression, it may cause problems")
        .with_label(span)
}

fn class(span: Span) -> OxcDiagnostic {
    OxcDiagnostic::warn("Do not add `then` to a class.")
        .with_help("If an object is defined as 'thenable', once it's accidentally used in an await expression, it may cause problems")
        .with_label(span)
}

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

declare_oxc_lint!(
    /// ### What it does
    ///
    /// Disallow defining a `then` property.
    ///

View on GitHub (pinned to e1e7af627c)

Solutions

1. Rename the export so the module namespace is not thenable
2. Wrap the value in a default or named object export instead of a bare `then` export

When it happens

Trigger: Thrown at crates/oxc_linter/src/rules/unicorn/no_thenable.rs:21 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/f0b595475b72efe4. Report an issue: GitHub.