prefer-object-has-own
Disallow use of Object.prototype.hasOwnProperty.call()
and prefer use of Object.hasOwn()
🔧 Fixable
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");
}
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")
}
Rule Details
Examples of incorrect code for this rule:
Open in Playground
/*eslint prefer-object-has-own: "error"*/
;
;
;
const hasProperty = ;
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);
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.