no-prototype-builtins & prefer-object-has-own

[erosman]

It is not an issue but I have noticed that with "no-prototype-builtins" enabled (i.e. with "extends": "eslint:recommended"), "prefer-object-has-own" is never shown (one is a subset of the other).
Is that expected?
Would that make "prefer-object-has-own" redundant (with "eslint:recommended")?

[Rec0iL99]

I don't think so. no-prototype-builtins is a rule that enforces using methods from Object.prototype instead of calling these methods directly on objects.

/* eslint no-prototype-builtins: "error" */
/* eslint prefer-object-has-own: "error" */

let hasBarProperty = Object.hasOwn(foo, "bar");

Here no-prototype-builtins is enforcing doing Object.prototype.hasOwnProperty.call(foo, "bar") instead of foo.hasOwnProperty("bar"), while the prefer-object-has-own enforces usage of Object.hasOwn(foo, "bar") instead of Object.prototype.hasOwnProperty.call(foo, "bar").

[erosman]

I should have included a code example.

/*eslint no-prototype-builtins: "error"*/
/*eslint prefer-object-has-own: "error"*/

const obj = {a: 1, b: 2};

console.log(obj.hasOwnProperty('a'));

Do not access Object.prototype method 'hasOwnProperty' from target object. (no-prototype-builtins)

[Rec0iL99]

Could you please provide more context?

[erosman]

As mentioned, this is not a problem. It is merely a curiosity. To start with, "prefer-object-has-own" does not generate a message in the following.

/*eslint prefer-object-has-own: "error"*/

const obj = {a: 1, b: 2};

console.log(obj.hasOwnProperty('a'));

[Rec0iL99]

prefer-object-has-own rule only enforces using Object.hasOwn(obj, 'a') instead of Object.prototype.hasOwnProperty.call(obj, 'a') since Object.hasOwn is an alias for Object.prototype.hasOwnProperty.call.

[erosman]

However ....

Object.hasOwn()

Note: Object.hasOwn() is intended as a replacement for Object.prototype.hasOwnProperty().

IMHO, the rule should also mark obj.hasOwnProperty('a').

/*eslint no-prototype-builtins: "error"*/
/*eslint prefer-object-has-own: "error"*/

const obj = {a: 1, b: 2};

obj.hasOwnProperty('a');
Object.hasOwnProperty.call(obj, 'a');
Object.prototype.hasOwnProperty(obj, 'a');
Object.prototype.hasOwnProperty.call(obj, 'a');