Quick deep cloning for JavaScript.
Unsafe for use on cyclical data structures. Does not copy functions as object properties.
Pass an object to clone as the first argument.
Pass true as the second argument to construct prototypes, empty or false to instantiate as plain objects.
Performance comes at a cost:
- no cyclic objects
- no protos that require arguments on construction (if
cast
flag istrue
) - no objects that shadow global proto properties
- no polluted base prototypes
clone(obj, cast = false)
const qdclone = require('quick-deep-clone');
let x = {
str: 'str',
num: 10,
arr: [0, 1, 2]
};
function A() {
this.str = 'str';
this.num = 10;
this.arr = [0, 1, 2];
}
// deep clone a plain object
console.log(qdclone(x));
// deep clone a prototyped object
console.log(qdclone(new A(), true));
// deep clone a prototyped object as a plain object
console.log(qdclone(new A(), false));
Package | Time (ms) |
---|---|
[email protected] | 1361 |
[email protected] | 1048 |
qdclone | 441 |
qdclone (* with casting) | 525 |
* only quick-deep-clone
supports casting prototypes
const { performance } = require('perf_hooks');
const cloners = {
'deep-clone': require('deep-clone'),
'rfdc': require('rfdc')(),
'qdclone': require('quick-deep-clone')
};
const ITERATIONS = 10000;
setImmediate(() => {
let x = makeX();
console.log('\nRunning...\n')
runBench('deep-clone', x, ITERATIONS);
runBench('rfdc', x, ITERATIONS);
runBench('qdclone', x, ITERATIONS);
console.log('Running with prototype casting (only supported by qdclone)...\n');
runBench('qdclone', x, ITERATIONS, true);
});
function runBench(type, obj, iterations, ...args) {
let cloned;
console.log(`Clone via ${type}...`);
let benchStart = performance.now();
for (let i = 0; i < iterations; ++i) {
cloned = cloners[type](obj, ...args);
}
console.log(`${performance.now() - benchStart} ms\n`);
return cloned;
}
function makeX() {
let x = {
str: 'str',
num: 10,
arr: [0, 1, 2],
date: new Date(),
bool: false,
sub: {
str2: 'abcdefghijklmnopqrstuvwxyz',
num2: 9999999.9999999,
bool2: true,
arr2: [-.0000001, true, 'asdf', 100000.00001, [1, 2, 3], 'loooooooooooong']
}
};
let x2 = {
x: JSON.parse(JSON.stringify(x))
};
let x3 = {
x: JSON.parse(JSON.stringify(x)),
x2: JSON.parse(JSON.stringify(x2))
};
let xs = [];
for (let i = 0; i < 100; ++i) {
xs.push(JSON.parse(JSON.stringify(x)));
}
return new class X {
constructor() {
this.x = x;
this.x2 = x2;
this.x3 = x3;
this.xs = xs;
}
}
}
Feel free to make changes and submit pull requests whenever.
Mousetouch uses the MIT license.