cloneDeep

1142 bytes

Usage

Deeply clone the given object or array. The only nested objects that get cloned by default are: plain objects, arrays, Map instances, and Set instances.

The default behavior aims to support the most popular use cases. See “Customized cloning” below if you need more control.

By default, non-enumerable properties and computed properties are copied lossless-ly. Note that you can opt out of this behavior if you need better performance (see “Faster cloning” below).

import * as _ from 'radashi'

_.cloneDeep()

Faster cloning

You can pass the FastCloningStrategy for better performance, but bear in mind the following tradeoff.

All plain objects and class instances are cloned with {...obj}. This means that the original prototype, computed properties, and non-enumerable properties are not preserved.

Also note that built-in, complex objects like RegExp and Date are still not cloned with this cloning strategy. You can override the cloneOther function if you need to clone these object types.

Customized cloning

“Cloning strategies” control how certain object types are handled by cloneDeep. You can pass in a custom strategy, which may even be a partial strategy. Any undefined methods in your strategy will inherit the default logic. Your custom methods can return null to use the default logic, or they can return the received object to skip cloning.

import * as _ from 'radashi'

_.cloneDeep(obj, {
  // Clone arrays with default logic if they are not frozen.
  cloneArray: array => (Object.isFrozen(array) ? array : null),
})

If you clone the object in your custom method, make sure to pass the clone into the track function before cloning the nested objects. Here’s an example with cloneOther that handles a custom class instance.

import * as _ from 'radashi'

_.cloneDeep(obj, {
  cloneOther: (obj, track, clone) => {
    if (obj instanceof MyClass) {
      // 1. Create a new instance and track it.
      const clone = track(new MyClass())

      // 2. Copy over the properties of the original instance.
      for (const key in obj) {
        clone[key] = clone(obj[key])
      }

      // 3. Return the cloned instance.
      return clone
    }

    // Use default logic for anything else.
    return null
  },
})