prefer-object-has-own

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

🔧

Some problems reported by this rule are automatically fixable by the --fix command line option

It is very common to write code like:

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

Examples of incorrect code for this rule:

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

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

Object.hasOwnProperty.call(obj, "a");

({}).hasOwnProperty.call(obj, "a");

const hasProperty = Object.prototype.hasOwnProperty.call(object, property);
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Examples of correct code for this rule:

Open in Playground

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

Object.hasOwn(obj, "a");

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

This rule has no options.

When Not To Use It

This rule should not be used unless ES2022 is supported in your codebase.

Version

This rule was introduced in ESLint v8.5.0.

Resources

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