Transaction Builder

TransactionBuilder is a fluent, chainable API for constructing UnsignedTransactionV1 objects. Instructions are appended in order and executed as a single batch on-chain.

Create a builder

import { TransactionBuilder, Network } from "@tari-project/ootle";

const builder = TransactionBuilder.new(Network.Esmeralda);

Build a transaction

A typical transaction: withdraw tokens from one account and deposit them into another.

const unsignedTx = TransactionBuilder.new(Network.Esmeralda)
  .feeTransactionPayFromComponent(accountAddress, 1000n)
  .callMethod(
    { componentAddress: accountAddress, methodName: "withdraw" },
    [{ Literal: resourceAddress }, { Literal: "500" }],
  )
  .saveVar("bucket")
  .callMethod(
    { componentAddress: recipientAddress, methodName: "deposit" },
    [{ Workspace: "bucket" }],
  )
  .buildUnsignedTransaction();

Method reference

Method	Description
`callFunction(func, args)`	Call a static function on a template
`callMethod(method, args)`	Call a method on a component
`createAccount(ownerPublicKey)`	Create a new account component
`createProof(account, resource)`	Create a resource proof
`claimBurn(claim, outputData)`	Claim a Minotari burn
`saveVar(name)`	Save last output to workspace
`feeTransactionPayFromComponent(addr, amount)`	Add fee instruction
`feeTransactionPayFromComponentConfidential(addr, proof)`	Confidential fee
`allocateAddress(type, name)`	Pre-allocate an address
`addInput(req)` / `withInputs(reqs)`	Add substate inputs
`withMinEpoch(n)` / `withMaxEpoch(n)`	Set epoch bounds
`withInstructions(instructions)`	Append raw instructions
`withFeeInstructions(instructions)`	Append raw fee instructions
`dropAllProofsInWorkspace()`	Drop all proofs
`buildUnsignedTransaction()`	Return the finished unsigned tx

Mutable builder pattern

All methods return this, so you can chain calls. The builder mutates its internal state — each call appends to the same instruction list:

// These are equivalent:
const tx1 = builder.callMethod(a, argsA).callMethod(b, argsB).buildUnsignedTransaction();

builder.callMethod(a, argsA);
builder.callMethod(b, argsB);
const tx2 = builder.buildUnsignedTransaction();