copying

copying is a library for making shallow copies. It requires you to make
particular decisions about how you want properties to be copied from one
object to another, to avoid ambiguity about what’s actually happening in the
copy.

This module exists to allow developers to make quick, deliberate decisions
about how properties ought to be copied between objects, without compromising
any clarity about what’s actually going on.

Usage

This module’s exports is a function that takes in a mandatory options object
with the following properties, and returns a copier function.

• enumerator: Must be one of the following string values:
  • "enumerable": The properties to copy will be iterated over using
    for .. in.
  • "ownKeys": The properties to copy will be retrieved using
    Reflect.ownKeys.
  • "keys": The properties to copy will be retrieved using Object.keys.
• chain: Boolean. If true, the prototype chain will also be iterated over,
  and prototype properties will be copied to destination objects (not to the
  destination prototypes). If false, the prototype chain will not be used.
• descriptor: Boolean. If true, properties will be copied by property
  descriptor. If false, properties will be copied by their resolved values.

Note: for .. in and Object.keys differ only in whether they include
items in the prototype chain. Since we’re deliberately choosing whether to
iterate over the prototype chain, enumerable and keys are equivalent
values for enumerator. Both are kept here, and implemented behind the scenes
using the two different methods, in case there are performance differences
between the two.

The returned copier function takes in objects similar to the way Object.assign
works. The first argument is the destination object to be copied to, and the
remaining arguments are source objects to be copied from, in the order they
appear.

Examples

TODO (For now, take a look at the tests.)

License

MIT License. See LICENSE.txt