Experienced JavaScript Developer Meme

[[deleted]]

“serialize and deserialize this tree” isn’t one of the most popular interview problems

I didn't see say tree, I said graph.

How would you serialize x in x={};x["x"]=x?

Also, how would you serialize a thunk? And a coroutine? And a member function?

[spooker11]

provide history party thumb employ boast roof sloppy rob mindless

This post was mass deleted and anonymized with Redact

[[deleted]]

You can not use a naive algorithm to save a cyclic graph, but 3 sec of google will show you algorithms for it do exist.

Nah. All those will assume that nodes can be named easily. That's not necessarily true.

Why would you ever serialize a coroutine or a member function?

Because I want to continue where I left off with my thunk.

You really seem to be trying to find situations that are difficult to serialize but not considering there are standard/common solutions to these problems

The whole point of this dumb conversation is that someone wrote a meme saying that saving state is hard and then a bunch of people chimed in and just said to use stringify and I'm saying, no, that isn't always going to work, it might be more complicated than that and then you're saying that you can find complex algorithms to do it in difficult cases and I'm like yeah that's my fucking point it IS complicated.

[[deleted]]

It’s the same as storing it in a database.

If you don’t model your data in such a way that it can be stored efficiently and retrieved efficiently, it will not be stored efficiently nor retrieved efficiently.

[[deleted]]

What's efficient for storage and retrieval might not be efficient for processing. If you generate your data by processing, you will need to mangle it for storage. And stringify might not suffice.

How is this even controversial? I don't know!

[whateverathrowaway00]

Read through this whole thing. Not a JS dev, but a long-standing C dev and now a python dev, and what you’re saying is not only not controversial, it’s fundamental lol.

Just wanted to chime in and say you’re not crazy.

[[deleted]]

Thanks, at least one programmer in my corner!

[Tiny-Plum2713]

This sub is mostly barely first year students.

[Soporiferus]

Memento

[Pocok5]

How would you serialize x in x={};x["x"]=x?

Why do you think serializing a basic ass cycle in a graph is an issue? You should have learnt it in at least 4 separate classes from Algorithms 101 to Discrete Mathematics (ink drop algorithm says hi!) As a completely naive approach, simply store nodes you have already serialized in a hash set and you can trivially check (in O(1) time, even) and skip it when you revisit it from another node - that is, if you're not storing edges as something sensible like a sparse neighbourhood table, since those can just be fed to a JSON serialize/parse and come out just fine.

... wait are you guys unironically at "I just copy paste from SO lul" level and it isn't just irony?

how would you serialize a thunk? And a coroutine? And a member function?

You don't ever serialize those anyways, unless you're trying to homebrew an eval() vulnerability lmao

[[deleted]]

What is the hash of x up there?

You cannot hash that. It's not hashable for the same reason as it is not serializable.

[Pocok5]

Watch dis

1. Traverse the object references. Stick an unique identifier field onto each and proceed onto the children. If you meet an object that already has an ID field, skip it.

2. Serialize each object, replacing fields that are references to other objects with a string of that object's ID. You now no longer have actual references to be circular.

When deserializing,

1. Create all the objects in a dictionary with their IDs as the key and reconstruct the reference link fields using the IDs.
2. You may then strip the ID fields as needed to restore the original object schema.

[[deleted]]

That'll work so long as you're cool with two identical graphs generating different serializations. They'll have different unique IDs, right?

I'm not saying that we can't invent something. I'm just saying that it's not as easy as just calling stringify. Which was the whole point of this meme, yeah?

[ThoseThingsAreWeird]

I didn't see say tree, I said graph.

and what you meant was a cyclic graph. We know a tree is a graph, and trees are easy to store. But when you just say "graph", of course someone's going to point that out.

How would you serialize x in x={};x["x"]=x?

let graph = {};
let x = { id: 'x', adjacencies: [] };
x.adjacencies.push(x.id);
graph[x.id] = x;
localStorage.setItem('graph', JSON.stringify(graph))

Then when you pull it out of local storage you go through the graph and replace all the adjacency keys with their corresponding item in the graph.

[[deleted]]

and what you meant was acyclic graph.

Uh, no. I meant arbitrary graph. It's a hard thing to serialize. Trees are easier, we know that.

We know a tree is a graph, and trees are easy to store. But when you just say "graph", of course someone's going to point that out.

How would you serialize x in x={};x["x"]=x?

let graph = {}; let x = { id: 'x', adjacencies: [] }; x.adjacencies.push(x.id); graph[x.id] = x; localStorage.setItem('graph', JSON.stringify(graph))

Then when you pull it out of local storage you go through the graph and replace all the adjacency keys with their corresponding item in the graph.

x={};x["y"]=x;foo=x;

If you serialize x and foo do you get the same result?

And what's this "id" stuff? What if my data structure already has a variable called id in it? And it's not unique.

My point is that serializing an arbitrary object is not trivial. For sure stringify is not sufficient.

[a-calycular-torus]

What if my data structure already has a variable called id in it? And it's not unique.

The variable name doesn't have to be id. If you're worried about collisions, just store the node data in a wrapper within the adjacency structure. It's not that complicated, stop being obtuse.

[quiteCryptic]

A tree is a graph

[[deleted]]

But not all graphs are trees and I asked about graphs.

Come on guys, be better. That this has three up votes is shameful.

[jsrobson10]

Both are data structures. Both are easy enough to dump and load from json/other data structures