Shallow clones an object while respecting the original property descriptors
npm install shallow-clone-shimShallow 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.
``
npm install shallow-clone-shim --save
`js
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)
`
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 anshim
object containing functions. The names of the object propeties isoriginal
expected to match the names of properties in the object. Eachoriginal
shim function is called with the property descriptor for that particular
property in . The function is expected to return a validObject.defineProperty()
property descriptor as expected by []. The
returned desciptor will replace the original descriptor in the copied
object.
[Object.defineProperty()`]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/defineProperty