Serializing and Deserializing args Array ?

[ilovedesert001]

hello , is there any way to serializing entire contract call returns and events ?

Currently I am using this to deserializing bignumber,

  JSON_parse(obj) {
    const func = (k, v) => {
      if (typeof v == "object" && v["type"] === "BigNumber") {
        return BigNumber.from(v);
      }

     //TODO fix args array

      return v;
    };
    return JSON.parse(obj, func);
  },

But because of the array used in ethers.js ( @ethersproject/abi/src.ts/coders/array.ts ) is vanilla array , I can't get my struct field back.

export function unpack(reader: Reader, coders: Array<Coder>): Result {
    let values: any = [];  // why it is just a normal array ???  , it should have a special mark (tag ? symbol , like bignumber's type )

    // A reader anchored to this base
    let baseReader = reader.subReader(0);
    ...

Is there any proper way to do this ?

eg:

contract.sol

    struct VeryComplexStruct {
        uint256 a;
        uint256 b;
        uint256 c;
        uint256 d;
    }

    function getStates() public returns (VeryComplexStruct memory) {
       ...
    }

goal: Once i get contract state (use a,b fieldName to access , not index) , I need to save them into localStorage , Next time user open the website , Load local cache first , then request latest data . (actually, it is mainly needed in events)

[ricmoo]

It just uses normal JavaScript objects when possible; BigNumber has special detection because it’s a class ethers provides.

To detect an array, you use the JavaScript Array.isArray(v). You will lose any name properties on it, as named parameters are added within the parsing functions.

[ilovedesert001]

is't this a problem ?
Can use name properties but can't serialize/ deserialize for later use ?

[ricmoo]

You can create a custom serialization format; which I would recommend if you are storing things in local storage, as you likely want to store additional metadata, such as when the data was placed in local storage, the account that it should be associated with (in case they change their connected metamask account, etc.). It's really up to how your application operates, but in general you should store the data you require, more so than store opaque values.

You might also wish to store your app version in the local storage, in case you change the contract or items in the future and have data formatted differently, so you can migrate data, or purge things, as necessary.

[ilovedesert001]

thanks ,
Yes, I am creating custom serialization format for events ,
but, now, I need to manually specify args and handle each of the different event types which is really annoying.
if the args array has some special marks , then I can handle this very easily.

  JSON_stringify(obj) {
    const func = (k, v) => {
      if (v  == 'is ether.js unpacked array') {   // TODO  I can't think of any other way than modifying the unpack function on the source code
        //properly get all (with decoded properties)
      }
      return v;
    };
    return JSON.stringify(obj, func, 2);
  },

[ricmoo]

That isn’t really possible though, since any tag added has the potential to conflict with a key. For example, imagine if the field was called ethersArray, then an event like event Foo(uint ethersArray) which would return an object like [ 1, ethersArray: 1 ].

Basically, adding properties to items that allow mega-class defined properties, require far more complexity and break some aspects of generality.

You should be able to use Array.isArray to detect any struct though.