GitHub - planttheidea/fast-copy: A blazing fast deep object copier
source link: https://github.com/planttheidea/fast-copy
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README.md
fast-copy
A blazing fast deep object copier
Table of contents
Usage
import copy from "fast-copy"; import { deepEqual } from "fast-equals"; const object = { array: [123, { deep: "value" }], map: new Map([["foo", {}], [{ bar: "baz" }, "quz"]]) }; const copiedObject = copy(object); console.log(copiedObject === object); // false console.log(deepEqual(copiedObject, object)); // true
Multiple realms
Under the hood, fast-copy
uses instanceof
to determine object types, which can cause false negatives when used in combination with iframe
-based objects. To handle this edge case, you can pass the optional second parameter of realm
to the copy
method, which identifies which realm the object comes from and will use that realm to drive both comparisons and constructors for the copies.
<iframe srcdoc="<script>var arr = ['foo', 'bar'];</script>"></iframe>
const iframe = document.querySelector("iframe"); const arr = iframe.contentWindow.arr; console.log(copy(arr, iframe.contentWindow)); // ['foo', 'bar']
Types supported
The following object types are deeply cloned when they are either properties on the object passed, or the object itself:
Array
ArrayBuffer
Buffer
DataView
Date
Float32Array
Float64Array
Int8Array
Int16Array
Int32Array
Map
Object
RegExp
Set
Uint8Array
Uint8ClampedArray
Uint16Array
Uint32Array
React
components- Custom constructors
The following object types are copied directly, as they are either primitives, cannot be cloned, or the common use-case implementation does not expect cloning:
AsyncFunction
Boolean
Error
Function
GeneratorFunction
Number
Null
Promise
String
Symbol
Undefined
WeakMap
WeakSet
Circular objects are supported out of the box as well. By default a cache based on WeakSet
is used, but if WeakSet
is not available then a standard Object
fallback is used. The benchmarks quoted below are based on use of WeakSet
.
Benchmarks
Simple objects
Small number of properties, all values are primitives
Operations / second Relative margin of error fast-copy 1,725,552 0.89% clone 1,114,295 0.82% lodash.cloneDeep 904,031 0.51% fast-deepclone 716,908 0.87% fast-clone 497,748 0.88% deepclone 420,962 0.59%
Complex objects
Large number of properties, values are a combination of primitives and complex objects
Operations / second Relative margin of error fast-copy 113,553 0.76% fast-deepclone 101,356 0.76% deepclone 54,401 0.80% clone 51,183 0.79% fast-clone 46,165 0.66% lodash.cloneDeep 39,395 0.78%
Circular objects
Objects that deeply reference themselves
Operations / second Relative margin of error fast-copy 1,011,337 0.80% clone 644,481 0.67% lodash.cloneDeep 577,534 0.48% fast-deepclone 359,288 0.79% deepclone 371,971 0.55% fast-clone (not supported) 0 0.00%
Special objects
Custom constructors, React components, etc
Operations / second Relative margin of error fast-copy 56,013 0.97% clone 42,107 0.87% lodash.cloneDeep 36,113 0.74% fast-deepclone 25,278 1.45% fast-clone 21,450 0.86% deepclone 12,768 0.77%
Development
Standard practice, clone the repo and npm i
to get the dependencies. The following npm scripts are available:
- benchmark => run benchmark tests against other equality libraries
- build => build dist files with
rollup
- clean => run
clean:dist
,clean:es
, andclean:lib
scripts - clean:dist => run
rimraf
on thedist
folder - clean:es => run
rimraf
on thees
folder - clean:lib => run
rimraf
on thelib
folder - dev => start webpack playground App
- dist => run
build
andbuild:minified
scripts - lint => run ESLint on all files in
src
folder (also runs ondev
script) - lint:fix => run
lint
script, but with auto-fixer - prepublish:compile => run
lint
,test:coverage
,transpile:lib
,transpile:es
, anddist
scripts - start => run
dev
- test => run AVA with NODE_ENV=test on all files in
test
folder - test:coverage => run same script as
test
with code coverage calculation vianyc
- test:watch => run same script as
test
but keep persistent watcher - transpile:es => run Babel on all files in
src
folder (transpiled toes
folder without transpilation of ES2015 export syntax) - transpile:lib => run Babel on all files in
src
folder (transpiled tolib
folder)
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