add helpers to make BigInt compatible with JSON.stringify

[hoangdv2429]

Currently we can have the option to encode/decode int64 as bigInt instead of Long. However, we're having a problem with display the response because JSON.stringify by default doesn't have the option to parse bigInt, as described in this issue. We should add helper to bigInt so that stringify can work with bigInt.

[Zetazzz]

const test= Proposal.fromPartial({
id: BigInt(1),
status: -1
})
// using toJSON can get string values of bigint inside
const testJson = Proposal.toJSON(test);
console.log(JSON.stringify(testJson));
// and then using fromJSON to get original Proposal type with bigint inside
const origTest = Proposal.fromJSON(testJson);
console.log(origTest)

I have to say it takes one more step... but this's currently the best we can do...

[Zetazzz]

I believe generating like this can solve the problem, and then we can make all functions that returns the interface(Proposal) using this creation:

function createBaseProposal(): Proposal {
return {
id: BigInt(0),
messages: [],
status: 0,
finalTallyResult: TallyResult.fromPartial({}),
submitTime: undefined,
depositEndTime: undefined,
totalDeposit: [],
votingStartTime: undefined,
votingEndTime: undefined,
metadata: "",
toJSON: function(){
return Proposal.toJSON(this)
}
} as Proposal;
}

I've tested and it's working:

const test= Proposal.fromPartial({
id: BigInt(1),
status: -1
})

// it will call toJSON inside and work
let testString = JSON.stringify(test);

console.log(testString);

let testJson = JSON.parse(testString)
// get back with the string id.
console.log(testJson)

// and then using fromJSON to get original Proposal type with bigint inside
const origTest = Proposal.fromJSON(testJson);
console.log(origTest)

Hope this make sense. If you like the solution, I can make the change.

[hoangdv2429]

Lgtm! We can add toJSON to createBase function that have bigInt fields and it should be good!

[hoangdv2429]

@Zetazzz can you review the PR above

[hoangdv2429]

let ppl define they own way of parsing object with bigInt