DEV Community

Important Javascript functions you have to know to be a better developer

Sam Sonter on March 05, 2022

Hi everybody, today I am going to show examples of few important Javascript functions. DEEP COPY JavaScript allows you to deep copy an ...

Read full post

Larson • Mar 5 '22 • Edited

You should not use JSON.stringify to clone object. It leads to problems because it can't strinigfy functions,symbol etc.

JSON.stringify({ 
    fun: () => console.log('lol'), 
    s: Symbol(), 
    u: undefined, 
    n: NaN, 
    in: Infinity
})
'{"n":null,"in":null}'

Just use lodash. Or write your own deep cloning algo. Or when using the browser you can use structuredClone (there are some limits too).

peerreynders • Mar 5 '22

Node.js 17.0.0 added structuredClone(value[, options])

Before that use v8.serialize(value) and v8.deserialize(buffer).

Then there is flatted which adds recursive references and RecursiveMap on top of JSON (still no functions, symbols, etc.).

Sam Sonter • Mar 5 '22

noted. thanks

Sam Sonter • Mar 5 '22

noted. thanks

Tamir • Mar 6 '22

"And you can google any of these if needed." reading relaxed me instantly.

Jackson Kasi • Mar 5 '22

wow, thanks, it's really helpful for me :)

CuriousDev • Mar 5 '22

Thank you and I would like to add, that creating a clone with JSON object (with parse and stringify) has some limitations! It will not work with every object.

codingjlu • Mar 7 '22

It's also important to remember that JSON.stringify cannot copy functions, so the "deep copy" only works for regular data types and objects.

Sam Sonter • Mar 6 '22

hhahahhahah. what work, works

Mateusz Skrobiś • Mar 11 '22

love that reply, thank u.

Sara (Risclover) • Mar 11 '22

These seem useful. Thanks for posting!

Sam Sonter • Mar 12 '22

you are welcome

Sanzhar Danybayev • Mar 20 '22

That's good too hear. I like your attitude. No offense. Might have misread your comment.

Hélio oliveira • Apr 11 '22

There is some typos. Like DECTECT , Andriod, prama, visiabilty.

Long Cui • Mar 13 '22

The "Wait" function is wrong. Please see @luke shiru's comment.

Sanzhar Danybayev • Mar 20 '22

Bro, you're a bit harsh. Though I would agree that title looks like a clickbait.

Sam Sonter • Mar 21 '22

I dont mind criticism. Its ok

Sanzhar Danybayev • Mar 22 '22

You're opened minded. Much respected!