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1# rfdc
2
3Really Fast Deep Clone
4
5
6[![build status](https://img.shields.io/travis/davidmarkclements/rfdc.svg)](https://travis-ci.org/davidmarkclements/rfdc)
7[![coverage](https://img.shields.io/codecov/c/github/davidmarkclements/rfdc.svg)](https://codecov.io/gh/davidmarkclements/rfdc)
8[![js-standard-style](https://img.shields.io/badge/code%20style-standard-brightgreen.svg?style=flat)](http://standardjs.com/)
9
10
11## Usage
12
13```js
14const clone = require('rfdc')()
15clone({a: 1, b: {c: 2}}) // => {a: 1, b: {c: 2}}
16```
17
18## API
19
20### `require('rfdc')(opts = { proto: false, circles: false }) => clone(obj) => obj2`
21
22#### `proto` option
23
24Copy prototype properties as well as own properties into the new object.
25
26It's marginally faster to allow enumerable properties on the prototype
27to be copied into the cloned object (not onto it's prototype, directly onto the object).
28
29To explain by way of code:
30
31```js
32require('rfdc')({ proto: false })(Object.create({a: 1})) // => {}
33require('rfdc')({ proto: true })(Object.create({a: 1})) // => {a: 1}
34```
35
36Setting `proto` to `true` will provide an additional 2% performance boost.
37
38#### `circles` option
39
40Keeping track of circular references will slow down performance with an
41additional 25% overhead. Even if an object doesn't have any circular references,
42the tracking overhead is the cost. By default if an object with a circular
43reference is passed to `rfdc`, it will throw (similar to how `JSON.stringify` \
44would throw).
45
46Use the `circles` option to detect and preserve circular references in the
47object. If performance is important, try removing the circular reference from
48the object (set to `undefined`) and then add it back manually after cloning
49instead of using this option.
50
51### `default` import
52It is also possible to directly import the clone function with all options set
53to their default:
54
55```js
56const clone = require("rfdc/default")
57clone({a: 1, b: {c: 2}}) // => {a: 1, b: {c: 2}}
58```
59
60### Types
61
62`rfdc` clones all JSON types:
63
64* `Object`
65* `Array`
66* `Number`
67* `String`
68* `null`
69
70With additional support for:
71
72* `Date` (copied)
73* `undefined` (copied)
74* `Buffer` (copied)
75* `TypedArray` (copied)
76* `Map` (copied)
77* `Set` (copied)
78* `Function` (referenced)
79* `AsyncFunction` (referenced)
80* `GeneratorFunction` (referenced)
81* `arguments` (copied to a normal object)
82
83All other types have output values that match the output
84of `JSON.parse(JSON.stringify(o))`.
85
86For instance:
87
88```js
89const rfdc = require('rfdc')()
90const err = Error()
91err.code = 1
92JSON.parse(JSON.stringify(e)) // {code: 1}
93rfdc(e) // {code: 1}
94
95JSON.parse(JSON.stringify({rx: /foo/})) // {rx: {}}
96rfdc({rx: /foo/}) // {rx: {}}
97```
98
99## Benchmarks
100
101```sh
102npm run bench
103```
104
105```
106benchDeepCopy*100: 457.568ms
107benchLodashCloneDeep*100: 1230.773ms
108benchCloneDeep*100: 655.208ms
109benchFastCopy*100: 747.017ms
110benchRfdc*100: 281.018ms
111benchRfdcProto*100: 277.265ms
112benchRfdcCircles*100: 328.148ms
113benchRfdcCirclesProto*100: 323.004ms
114```
115
116## Tests
117
118```sh
119npm test
120```
121
122```
123169 passing (342.514ms)
124```
125
126### Coverage
127
128```sh
129npm run cov
130```
131
132```
133----------|----------|----------|----------|----------|-------------------|
134File | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s |
135----------|----------|----------|----------|----------|-------------------|
136All files | 100 | 100 | 100 | 100 | |
137 index.js | 100 | 100 | 100 | 100 | |
138----------|----------|----------|----------|----------|-------------------|
139```
140
141## License
142
143MIT
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