I am using React+Typescript and trying to retrieve data from a struc using a query subscription. I first tried the following in order to check that I'm retrieving the right data:

api.query.rolesModule.requestedRoles(address, (data: Codec) => {
      let data0 = data.toString();
      console.log('In session:' + data0);

the string returned is the following:

In session:{"accountId":"5D1nJ8*************uc5e3AuB","role":"SELLER","block":2600,"proposalHash":"0xf0e4d3819cad58b9b7a521968202192601654106b063ed550d45e949cd0f9eec","proposalIndex":0,"sessionClosed":false,"approved":false}

Now what I really want are the role and block fields. I tried the following:

      ({ block, role }: { block: number; role: string }) => {
        let data0 = block;
        let data1 = role;
        console.log('In session:' + data0 + ' & ' + data1);

but both results are undefined (which is not actually the case). I did my best to emulate the example in the polkadot.js API doc, and had success in the following case to recover the free balance:

 api.query.system.account(address, ({ data: free }: { data: { free: BN } }) => {
      let { free: balance1 } = free;

What am I missing?

Edit1: This is the storage I am trying to get data from:

    #[pallet::getter(fn get_requested_role)]
    pub type RequestedRoles<T: Config> =
        StorageMap<_, Twox64Concat, AccountIdOf<T>, Proposal<T>, OptionQuery>;

with proposal being:

pub struct Proposal<T: Config>{
    pub account_id: T::AccountId,
    pub role: Option<Accounts>,
    pub block: BlockNumberOf<T>,
    pub proposal_hash: T::Hash,
    pub proposal_index: u32,
    pub session_closed: bool, 
    pub approved: bool,

thanks in advance Kazu

1 Answer 1


You can call toHuman() it returns Human-parsable JSON structure with values formatted as per the settings.

This example will return you the values you are trying to get.

api.query.templateModule.requestedRoles(address, (data: any) => {
        let data0 = data.toHuman();

toHuman() returns an any, if you want to have it all typed I suggest you create a parse function that get this any input an returns your custom type Proposal

  • Thanks Alex!! this exactly what I needed!!I only wish I could use another type than any for data, as I'm on TS...... Aug 3, 2023 at 9:00
  • WIth the Codec you were using doesn't work?
    – Alex Bean
    Aug 3, 2023 at 9:42
  • no, it does not find the different fields with codec Aug 3, 2023 at 10:35

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