#prefer-object-has-own

#Configuration

import { defineConfig, js } from '@rslint/core';

export default defineConfig([
  js.configs.recommended,
  {
    rules: {
      'prefer-object-has-own': 'error',
    },
  },
]);

#Rule Details

Object.prototype.hasOwnProperty.call(object, property) is the long-standing way to ask whether an object has a property of its own without going through the object's own hasOwnProperty, which may be missing or redefined. Object.hasOwn(), introduced in ES2022, asks the same question directly.

This rule reports a call to hasOwnProperty reached through the global Object, Object.prototype, or an empty object literal, and offers Object.hasOwn() in its place.

Examples of incorrect code for this rule:

Object.prototype.hasOwnProperty.call(object, 'foo');

Object.hasOwnProperty.call(object, 'foo');

({}).hasOwnProperty.call(object, 'foo');

const hasProperty = Object.prototype.hasOwnProperty.call(object, property);

Examples of correct code for this rule:

Object.hasOwn(object, 'foo');

const hasProperty = Object.hasOwn(object, property);

object.hasOwnProperty('foo');

foo.hasOwnProperty.call(object, 'foo');

function check(Object) {
  return Object.prototype.hasOwnProperty.call(object, 'foo');
}

#Options

This rule has no options.

#When Not To Use It

Use this rule only where ES2022 is available: Object.hasOwn() does not exist in older runtimes.

#Differences from ESLint

• A TypeScript declaration that binds the name Object as a type only — a type alias, an interface, or a type parameter — leaves the call reported; ESLint stays silent on the whole file. A value declaration (const Object, class Object, import Object from …, declare const Object) silences the report in both.

#Original Documentation

• ESLint: prefer-object-has-own
• Source code