There are two invariant types of transactions in the Apophis SDK:
  • CosmosTx is the fundamental transaction type for all transactions in Cosmos, including
  • CosmosTxSignal, which wraps a CosmosTx into multiple signals specialized for use in a GUI.

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CosmosTx

TODO

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CosmosTxSignal

A CosmosTxSignal is an invariant that wraps a CosmosTx with various signals for use in a GUI. Unlike the regular CosmosTx, this invariant takes a signal of messages, and automatically updates and re-estimates the gas of the transaction when the messages change. It also periodically refreshes the estimage to account for changes in the state of the blockchain while the user is still contemplating their transaction. The following example demonstrates the use of the Cosmos.signalTx factory method using Preact as its frontend framework: 
import { signals } from '@apophis-sdk/core';
import { Apophis, Bank, Cosmos, DefaultCosmosMiddlewares } from '@apophis-sdk/cosmos';
import { useComputed } from 'preact/signals';
import { useMemo } from 'preact/hooks';

Apophis.use(...DefaultCosmosMiddlewares);

Cosmos.getNetworkFromRegistry('neutrontestnet').then(network => {
  signals.network.value = network;
});

function MyComponent() {
  // There is no base type for messages. The only thing that matters is that the SDK knows how to
  // serialize and deserialize them, which is implemented through the middleware subsystem.
  const msgs = useComputed(() => [
    new Bank.Send({
      fromAddress: signals.address.value,
      toAddress: 'neutron1...', // e.g. your own address
      amount: [Cosmos.coin(1_000000n, 'untrn')], // 1 NTRN
    }),
  ]);

  const tx = useMemo(() => Cosmos.signalTx(msgs));

  return (
    <div>
      <button onClick={() => tx.signAndBroadcast()}>
        Send payment
      </button>
      <cosmos-gas-estimate tx={tx} />
    </div>
  );
}
The above cosmos-gas-estimate component is a custom element from the complementary Cosmos Components library.