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TxBuilder

plu-ts/offchain exposes the TxBuilder class.

How to use​

Its purpose is to allow you to build transactions more easly.

You could infact build transactions by calling the Tx constructor.

However that requires a profound understanding of the structure of a Cardano transaction.

for this reason we have the TxBuilder.

You can get your TxBuilder by passing the ProtocolParameters (that you'll need to query) needed for the network you are building transactions for.

constructor definiton:

constructor(
    protocolParamters: Readonly<ProtocolParameters>,
    genesisInfos?: GenesisInfos
)

example:

type MyFavoriteServiceResponse = any

// you'll need to adapt the protocol parameters
// to the expected interface
function adaptServiceProtocolParams(
    response: MyFavoriteServiceResponse
): ProtocolParameters
{
    /* do your magic */
}

const txBuilder = new TxBuilder(
    adaptServiceProtocolParams(
        await fetch("my-favorite-service.com/api/protocol-parameters")
    )
);

Methods​

once you have your tx builder you can use all the following methods.

buildSync or runWithProvider​

once you have a TxBuilder instance there are 2 ways to build a transaction:

  1. using buildSync
  2. getting a TxBuilderRunner by passing a Partial<IProvider> to the runWithProvider method

Pro and Cons​

The buildSync method gives you full controll, you need to query the resolved utxos for the inputs, as well any other information required for transaction validation.

Once you provide the data as specified in by ITxBuildArgs the TxBuilder instance will syncronously build and validate your transaction.

If you don't want to take care of querying the data, you can pass a Provider to the runWithProvider method, to get a TxBuilderRunner instance.

The runner has many method that abstract the buildSync interface, so that you can describe your transaction an a much higher level, and if some that is missing it will be queried asynchronously using the Provider that was passed.