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eslint/prefer-object-has-own Style

🛠️ An auto-fix is available for this rule for some violations.

What it does

Disallow use of Object.prototype.hasOwnProperty.call() and prefer use of Object.hasOwn()

Why is this bad?

It is very common to write code like:

if (Object.prototype.hasOwnProperty.call(object, "foo")) {
  console.log("has property foo");
}

This is a common practice because methods on Object.prototype can sometimes be unavailable or redefined (see the no-prototype-builtins rule). Introduced in ES2022, Object.hasOwn() is a shorter alternative to Object.prototype.hasOwnProperty.call():

if (Object.hasOwn(object, "foo")) {
  console.log("has property foo");
}

Examples

Examples of incorrect code for this rule:

Object.prototype.hasOwnProperty.call(obj, "a");
Object.hasOwnProperty.call(obj, "a");
({}).hasOwnProperty.call(obj, "a");
const hasProperty = Object.prototype.hasOwnProperty.call(object, property);

Examples of correct code for this rule:

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

How to use

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

Config (.oxlintrc.json)

{
  "rules": {
    "prefer-object-has-own": "error"
  }
}

Config (oxlint.config.ts)

import { defineConfig } from "oxlint";

export default defineConfig({
  rules: {
    "prefer-object-has-own": "error",
  },
});

CLI

oxlint --deny prefer-object-has-own

Version

This rule was added in v0.11.0.

References

• Rule Source
• Upstream rule docs
• Open rule in Oxc Playground