oxc-project/oxc · error · OxcDiagnostic

Use `{to_be_literal}` instead of `{matcher_name}`.

Error message

Use `{to_be_literal}` instead of `{matcher_name}`.

What it means

Emitted by the vitest/prefer-strict-boolean-matchers rule at an expectation using the loose boolean matchers `toBeTruthy()`/`toBeFalsy()`. It fires because these matchers accept any truthy/falsy value; strict `toBe(true)`/`toBe(false)` assertions catch accidental non-boolean values.

Source

Thrown at crates/oxc_linter/src/rules/vitest/prefer_strict_boolean_matchers.rs:16

use oxc_ast::{AstKind, ast::Expression};
use oxc_diagnostics::OxcDiagnostic;
use oxc_macros::declare_oxc_lint;
use oxc_span::Span;

use crate::{
    context::LintContext,
    rule::Rule,
    utils::{PossibleJestNode, parse_expect_and_typeof_vitest_fn_call},
};

fn prefer_strict_boolean_matchers_diagnostic(span: Span, value: bool) -> OxcDiagnostic {
    let (matcher_name, to_be_literal) =
        if value { ("toBeTruthy", "toBe(true)") } else { ("toBeFalsy", "toBe(false)") };

    OxcDiagnostic::warn(format!("Use `{to_be_literal}` instead of `{matcher_name}`."))
        .with_help("Use strict boolean comparison instead of truthy/falsy coercion.")
        .with_label(span)
}

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

declare_oxc_lint!(
    /// ### What it does
    ///
    /// Enforce using `toBe(true)` and `toBe(false)` over matchers that coerce types to boolean.
    ///
    /// ### Why is this bad?
    ///
    /// Truthy/falsy matchers coerce values to boolean and can hide type mistakes.
    /// Strict boolean assertions make intent explicit and avoid accidental coercion.
    ///
    /// ### Examples

View on GitHub (pinned to e1e7af627c)

Solutions

1. Replace `toBeTruthy()` with `toBe(true)` and `toBeFalsy()` with `toBe(false)`

When it happens

Trigger: Thrown at crates/oxc_linter/src/rules/vitest/prefer_strict_boolean_matchers.rs:16 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/fdc8b44e08e9f1bf. Report an issue: GitHub.