shallow-clone-shim
Shallow clones an object, including non-enumerable properties, while respecting the original data and accessor descriptors of the properties. This means that for instances getters and setters are copied faithfully. Optionally allows for shimming/overwriting properties by redefining or manipulating existing property descriptors.
Installation
npm install shallow-clone-shim --save
Usage
const assert = require('assert')
const clone = require('shallow-clone-shim')
const original = Object.defineProperties({}, {
foo: { // non-writable
value: 1
},
bar: { // non-configurable
enumerable: true,
get: function get () {
return 2
}
}
})
assert.strictEqual(original.foo, 1)
assert.strictEqual(original.bar, 2)
const copy = clone({}, original, {
bar (descriptor) {
// descriptor == Object.getOwnPropertyDescriptor(original, 'bar')
const getter = descriptor.get
descriptor.get = function get () {
return getter() + 1
}
return descriptor
}
})
assert.strictEqual(original.foo, 1)
assert.strictEqual(original.bar, 3)
API
object = clone(object, original[, shim])
Shallow copies all own properties of the original
into object
. Both
enumerable and non-enumerable properties are copied.
The object
is also returned.
If the optional shim
argument is supplied, it's expected to be an
object containing functions. The names of the shim
object propeties is
expected to match the names of properties in the original
object. Each
shim function is called with the property descriptor for that particular
property in original
. The function is expected to return a valid
property descriptor as expected by Object.defineProperty()
. The
returned desciptor will replace the original descriptor in the copied
object.