vitest/prefer-to-be-falsy Style

🛠️ An auto-fix is available for this rule.

What it does

This rule warns when toBe(false) is used with expect or expectTypeOf. With --fix, it will be replaced with toBeFalsy().

Why is this bad?

Using toBe(false) is less expressive and may not account for other falsy values like 0, null, or undefined. toBeFalsy() provides a more comprehensive check for any falsy value, improving the robustness of the tests.

Examples

Examples of incorrect code for this rule:

expect(foo).toBe(false);
expectTypeOf(foo).toBe(false);

Examples of correct code for this rule:

expect(foo).toBeFalsy();
expectTypeOf(foo).toBeFalsy();

How to use

To enable this rule in the CLI or using the config file, you can use:

CLI

oxlint --deny vitest/prefer-to-be-falsy --vitest-plugin

Config (.oxlintrc.json)

{
  "plugins": ["vitest"],
  "rules": {
    "vitest/prefer-to-be-falsy": "error"
  }
}

References

• Rule Source