jest/prefer-to-contain Style

🛠️ An auto-fix is available for this rule.

What it does

In order to have a better failure message, toContain() should be used upon asserting expectations on an array containing an object.

Why is this bad?

This rule triggers a warning if toBe(), toEqual() or toStrictEqual() is used to assert object inclusion in an array

Examples

Examples of incorrect code for this rule:

expect(a.includes(b)).toBe(true);
expect(a.includes(b)).not.toBe(true);
expect(a.includes(b)).toBe(false);
expect(a.includes(b)).toEqual(true);
expect(a.includes(b)).toStrictEqual(true);

Examples of correct code for this rule:

expect(a).toContain(b);
expect(a).not.toContain(b);

This rule is compatible with eslint-plugin-vitest, to use it, add the following configuration to your .oxlintrc.json:

{
  "rules": {
     "vitest/prefer-to-contain": "error"
  }
}

How to use

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

Config (.oxlintrc.json)

{
    "plugins": ["jest"],
    "rules": {
        "jest/prefer-to-contain": "error"
    }
}

CLI

oxlint --deny jest/prefer-to-contain --jest-plugin

References

• Rule Source