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);