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Rule suggestion - Prevent using built-in prototype properties on an object

See original GitHub issue

Prevent use of built-in prototype properties on an object as these won’t work on objects without a prototype, eg. object created with Object.create(null). You never know when you’ll get an object like that, so better be safe than sorry. This rule would have prevented #2688.

Should prevent the use of these:

//=> ["constructor", "toString", "toLocaleString", "valueOf", "hasOwnProperty", "isPrototypeOf", "propertyIsEnumerable", "__defineGetter__", "__lookupGetter__", "__defineSetter__", "__lookupSetter__", "__proto__"]

Example of misuse:

var obj = {}; = true;
//=> true

Which will fail here:

var obj = Object.create(null); = true;
//=> 'Uncaught TypeError: obj.hasOwnProperty is not a function'

Instead this should be used:

var obj = Object.create(null); = true;, 'foo');
//=> 'foo'


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Issue Analytics

  • State:closed
  • Created 8 years ago
  • Comments:43 (43 by maintainers)

github_iconTop GitHub Comments

ilyavolodincommented, May 4, 2016

I’ll support this. It’s a pretty important rule rule that’s hard for new users to understand without learning more about prototypical inheritance. So I think it can save people from creating a lot of errors.

Read more comments on GitHub >

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