oxc-project/oxc · error · OxcDiagnostic

The use of `toBeCalledTimes(1)` and `toHaveBeenCalledTimes(1

Error message

The use of `toBeCalledTimes(1)` and `toHaveBeenCalledTimes(1)` is discouraged.

What it means

Emitted by the vitest/prefer-called-once rule at an expectation using `toBeCalledTimes(1)` or `toHaveBeenCalledTimes(1)`. It fires because asserting exactly one call is better written with the dedicated `toHaveBeenCalledOnce()` matcher, which is clearer and gives better failure messages.

Source

Thrown at crates/oxc_linter/src/rules/vitest/prefer_called_once.rs:13

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

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

fn prefer_called_once_diagnostic(span: Span, new_matcher_name: &str) -> OxcDiagnostic {
    OxcDiagnostic::warn(
        "The use of `toBeCalledTimes(1)` and `toHaveBeenCalledTimes(1)` is discouraged.",
    )
    .with_help(format!("Prefer `{new_matcher_name}()`."))
    .with_label(span)
}

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

declare_oxc_lint!(
    /// ### What it does
    ///
    /// Substitute `toBeCalledTimes(1)` and `toHaveBeenCalledTimes(1)` with
    /// `toBeCalledOnce()` and `toHaveBeenCalledOnce()` respectively.
    ///
    /// ### Why is this bad?
    ///
    /// The `*Times` matchers require reading the argument to know how many

View on GitHub (pinned to e1e7af627c)

Solutions

1. Replace `toBeCalledTimes(1)` / `toHaveBeenCalledTimes(1)` with `toHaveBeenCalledOnce()`

When it happens

Trigger: Thrown at crates/oxc_linter/src/rules/vitest/prefer_called_once.rs:13 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/c3f90a26cf261484. Report an issue: GitHub.