copy-own

copy-own

Copies an object’s own properties to another object.

“Own” properties are those that are not inherited from the prototype chain.

Installation

Requires Node.js 6.0.0 or above.

npm i copy-own

API

The module exports a single function.

Parameters

1. from (object): The source object that possesses the properties to be copied.
2. Optional: to (object): The destination object that should receive the copied properties. Defaults to a new object.
3. Optional: Object argument:
   • enumOnly (boolean): Whether or not to limit the copy operation to only those properties that were defined with the enumerable flag. Defaults to false.
   • override (boolean): If omitted or set to true, all properties will be copied (unless overwrite specifies otherwise). If set to false, then existing properties in to will be neither overwritten nor overridden; that is, the copy operation will only include properties that do not share a name with properties already existing in to or in its prototype chain.
   • overwrite (boolean): This property is only taken into consideration if override (see above) is omitted or set to true. If this property is also omitted or set to true, all properties will be copied (the default behavior). If set to false, then existing properties in to will not be overwritten, but properties higher up in to’s prototype chain could still be overridden.

Return Value

The function modifies the second argument (to) and returns it. If to is omitted, a new object is created and returned.

Examples

const copyOwn = require('copy-own')

const from = {a: 'from', b: 'from'}
const to = {b: 'to', c: 'to'}
const to = copyOwn(from, to)
to.a // 'from'
to.b // 'from'
to.c // 'to'

Here is the same example repeated with overwrite set to false:

const copyOwn = require('copy-own')

const from = {a: 'from', b: 'from'}
const to = {b: 'to', c: 'to'}
const to = copyOwn(from, to, {overwrite: false})
to.a // 'from'
to.b // 'to'
to.c // 'to'

When no destination object is specified, a new object is created:

const copyOwn = require('copy-own')

const from = {a: 1, b: 2}
const to = copyOwn(from)
to.a // 1
to.b // 2