Example script

broken-query-example.js

  async subscribeTokenBalance(
    address: string,
    assets: Asset[],
    onChange: (balances: [string, BigNumber][]) => void
  ): UnsubscribePromise {
    const supported = assets
      .filter((a) => a.type !== 'Erc20')
      .filter((a) => a.id !== SYSTEM_ASSET_ID);

    const callArgs = supported.map((a) => [address, a.id]);
    return this.api.query.tokens.accounts.multi(callArgs, (balances) => {
      console.log('===========', new Date().toLocaleString(), '===========');
      const result: [string, BigNumber][] = [];
      balances.forEach((data, i) => {
        const freeBalance = this.calculateFreeBalance(data);
        const token = callArgs[i][1];
        console.log(address, token, freeBalance.toString());
        result.push([token, freeBalance]);
      });
      onChange(result);
    });
  }