Disallow use of Object.prototypes builtins directly (no-prototype-builtins)

In ECMAScript 5.1, Object.create was added, which enables the creation of objects with a specified [[Prototype]]. Object.create(null) is a common pattern used to create objects that will be used as a Map. This can lead to errors when it is assumed that objects will have properties from Object.prototype. This rule prevents calling some Object.prototype methods directly from an object.

Rule Details

This rule disallows calling some Object.prototype methods directly on object instances.

Examples of incorrect code for this rule:

/*eslint no-prototype-builtins: "error"*/

var hasBarProperty = foo.hasOwnProperty("bar");

var isPrototypeOfBar = foo.isPrototypeOf(bar);

var barIsEnumerable = foo.propertyIsEnumerable("bar");

Examples of correct code for this rule:

/*eslint no-prototype-builtins: "error"*/

var hasBarProperty = Object.prototype.hasOwnProperty.call(foo, "bar");

var isPrototypeOfBar = Object.prototype.isPrototypeOf.call(foo, bar);

var barIsEnumerable = {}.propertyIsEnumerable.call(foo, "bar");

When Not To Use It

You may want to turn this rule off if you will never use an object that shadows an Object.prototype method or which does not inherit from Object.prototype.

Version

This rule was introduced in ESLint 2.11.0.

Resources

• Rule source
• Documentation source