jest/prefer-to-contain Style
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?
TThis rule triggers a warning if toBe()
, toEqual()
or toStrictEqual()
is used to assert object inclusion in an array
Example
javascript
// valid
expect(a).toContain(b);
expect(a).not.toContain(b);
// invalid
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);