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clone-deep-circular-referencesTypeScript icon, indicating that this package has built-in type declarations

2.0.0 • Public • Published

clone-deep-circular-references

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Shallow object colone and recursively (deep) clone JavaScript objects that handles circular references.

This is a reimplementation of the package clone-deep to allow have circular references; as well, a reimplementation of shallow-clone to make it friendly with webpack.

Install

Install with npm:

$ npm install --save clone-deep-circular-references

Basic usage

In this way you need to call the cloneDeep or the cloneShallow function passing as first argument the value to clone.

import { cloneDeep, cloneShallow } from 'clone-deep-circular-references';
 
let obj = { a: 'b' };
let arr = [obj];
let deepCopy = cloneDeep(arr);
let shallowCopy = cloneShallow(arr);
obj.c = 'd';
shallowCopy.push('hello');
 
console.log(deepCopy);
//=> [{ a: 'b' }]
 
console.log(arr);
//=> [{ a: 'b', c: 'd' }]
 
console.log(shallowCopy);
//=> [{ a: 'b', c: 'd' }, 'hello']

Cloning custom classes

By default, if a no plain object is found, no copy will be created; if you want to change it, you need to specify true as second argument. Note: in this way the class's constructor will not be called (a new object with the same prototype will be created), and then each property will be set.

import { cloneDeep, cloneShallow } from 'clone-deep-circular-references';
 
class MyClass {
    constructor(value) {
        this.prop = value;
    }
}
let obj = { a: new MyClass('b') };
 
let deepCopy = cloneDeep(arr);
console.log(obj === deepCopy);
//=> true
console.log(obj.a === deepCopy.a);
//=> true
 
deepCopy = cloneDeep(arr, true);
console.log(obj === deepCopy);
//=> false
console.log(obj.a === deepCopy.a);
//=> false
 
let shallowCopy = cloneShallow(arr);
console.log(obj === shallowCopy);
//=> true
console.log(obj.a === shallowCopy.a);
//=> true
 
shallowCopy = cloneShallow(arr, true);
console.log(obj === shallowCopy);
//=> false
console.log(obj.a === shallowCopy.a);
//=> true

Controlling how custom classes are cloned

If you want to control how how no plain objects are copied you can specify a function as second argument that copy the value; this function receives as first argument the value to clone and as second argument the a Map with the object already cloned.

Note: if inside the cloneDeep function you want to call the cloneDeep function you need to pass a third argument the map with the object already cloned.

import { cloneDeep, cloneShallow } from 'clone-deep-circular-references';
 
class MyClass {
    constructor(value) {
        this.prop = value;
    }
}
let obj = { a: new MyClass('b') };
 
let deepCopy = cloneDeep(arr, function myCustomClone(value, instancesMap) {
    if (value instanceof MyClass) {
        return new MyClass(value.prop)
    }
    return cloneDeep(value, myCustomClone, instancesMap);
});
 
console.log(obj === deepCopy);
//=> false
 
console.log(obj.a === deepCopy.a);
//=> false
 
let shallowCopy = cloneShallow(arr, function myCustomClone(value) {
    if (value instanceof MyClass) {
        return new MyClass(value.prop)
    }
    return cloneShallow(value, myCustomClone);
});
 
console.log(obj === shallowCopy);
//=> false
 
console.log(obj.a === shallowCopy.a);
//=> true

Handled types

The following types are handled recursively by the cloneDeep function:

  • Plain objects
  • No plain objects (see the previous documentation)
  • Arrays
  • Map
  • Set

The other object types are copied using the cloneShallowfunction.

The following types are handled by the cloneShallow function:

  • Plain objects
  • No plain objects (see the previous documentation)
  • Arrays
  • Map
  • Set
  • Date
  • RegExp
  • Error

The following types are returned without create a copy:

  • Symbol
  • Promise
  • WeakMap
  • WeakSet
  • Buffer (nodejs)
  • ArrayBuffer
  • Int8Array
  • Uint8Array
  • Uint8ClampedArray
  • Int16Array
  • Uint16Array
  • Int32Array
  • Uint32Array
  • Float32Array
  • Float64Array
  • undefined
  • null
  • boolean
  • string
  • number
  • function
  • iterator
  • any other special JavaScript object

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License

MIT

Install

npm i clone-deep-circular-references

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Version

2.0.0

License

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