for-in

Iterate over the own and inherited enumerable properties of an object, and return an object with properties that evaluate to true from the callback. Exit early by returning `false`. JavaScript/Node.js

union-value

Set an array of unique values as the property of an object. Supports setting deeply nested properties using using object-paths/dot notation.

has-proto

Does this environment have the ability to get the [[Prototype]] of an object on creation with `__proto__`?