Really Fast Deep Clone
const clone = require('rfdc')()
clone({a: 1, b: {c: 2}}) // => {a: 1, b: {c: 2}}
Copy prototype properties as well as own properties into the new object.
It's marginally faster to allow enumerable properties on the prototype to be copied into the cloned object (not onto it's prototype, directly onto the object).
To explain by way of code:
require('rfdc')({ proto: false })(Object.create({a: 1})) // => {}
require('rfdc')({ proto: true })(Object.create({a: 1})) // => {a: 1}
Setting proto
to true
will provide an additional 2% performance boost.
Keeping track of circular references will slow down performance with an
additional 25% overhead. Even if an object doesn't have any circular references,
the tracking overhead is the cost. By default if an object with a circular
reference is passed to rfdc
, it will throw (similar to how JSON.stringify
would throw).
Use the circles
option to detect and preserve circular references in the
object. If performance is important, try removing the circular reference from
the object (set to undefined
) and then add it back manually after cloning
instead of using this option.
It is also possible to directly import the clone function with all options set to their default:
const clone = require("rfdc/default")
clone({a: 1, b: {c: 2}}) // => {a: 1, b: {c: 2}}
rfdc
clones all JSON types:
Object
Array
Number
String
null
With additional support for:
Date
(copied)undefined
(copied)Buffer
(copied)TypedArray
(copied)Map
(copied)Set
(copied)Function
(referenced)AsyncFunction
(referenced)GeneratorFunction
(referenced)arguments
(copied to a normal object)
All other types have output values that match the output
of JSON.parse(JSON.stringify(o))
.
For instance:
const rfdc = require('rfdc')()
const err = Error()
err.code = 1
JSON.parse(JSON.stringify(e)) // {code: 1}
rfdc(e) // {code: 1}
JSON.parse(JSON.stringify({rx: /foo/})) // {rx: {}}
rfdc({rx: /foo/}) // {rx: {}}
npm run bench
benchDeepCopy*100: 457.568ms
benchLodashCloneDeep*100: 1230.773ms
benchCloneDeep*100: 655.208ms
benchFastCopy*100: 747.017ms
benchRfdc*100: 281.018ms
benchRfdcProto*100: 277.265ms
benchRfdcCircles*100: 328.148ms
benchRfdcCirclesProto*100: 323.004ms
npm test
169 passing (342.514ms)
npm run cov
----------|----------|----------|----------|----------|-------------------|
File | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s |
----------|----------|----------|----------|----------|-------------------|
All files | 100 | 100 | 100 | 100 | |
index.js | 100 | 100 | 100 | 100 | |
----------|----------|----------|----------|----------|-------------------|
MIT