🚀FCT Builder

The FCT Builder Library simplifies the creation, management, and compilation of graph-based representations of Ethereum transactions. It leverages the FCT Plugins to interact with the blockchain.

Overview

The library contains several key classes and interfaces that work together to build a graph representing a transaction flow:

• FCTGraph: Core class representing the graph structure.

• WrappedPlugin: Represents a wrapped instance of a plugin within the graph.

• Param: Class representing a parameter of a plugin instance.

Usage

1. Create a new graph instance

To start, create a new graph instance using the create() function:

import { create } from 'ki-fct-builder';
const fct = create();

2. Add nodes to the graph

Add nodes to the graph using the add() method.

The example below demonstrates adding nodes for various operations, including an ERC20 BalanceOf getter, a GreaterThan validator, and ERC20 Transfer actions for two different recipients:

import { ERC20, Validator } from 'ki-fct-corelib';

const getMyKiroBalance = fct.add(ERC20.getters.BalanceOf, {
  to: KIRO_ADDR,
  methodParams: {
    owner: MY_WALLET,
  },
});

const isGreaterThan1000 = fct.add(Validator.getters.GreaterThan, {
  methodParams: {
    value1: getMyKiroBalance.outputs.balance,
    value2: parseUnits('1000', 18).toString(),
  },
});

const sendAllKiroToBob = fct.add(ERC20.actions.Transfer, {
  to: KIRO_ADDR,
  methodParams: {
    amount: getMyKiroBalance.outputs.balance,
    to: BOB_WALLET_ADDR,
  },
});

const sendAllKiroToAlice = fct.add(ERC20.actions.Transfer, {
  to: KIRO_ADDR,
  methodParams: {
    amount: getMyKiroBalance.outputs.balance,
    to: ALICE_WALLET_ADDR,
  },
});

Visualization

3. Connect nodes and set the start node

Use the then(), onFail(), and onEither() methods to connect nodes and define the flow of the graph. Set the starting node using startWith():

fct.startWith(
  getMyKiroBalance.then(
    isGreaterThan1000
      .then(sendAllKiroToBob)
      .onFail(sendAllKiroToAlice)
  )
);

Note that each plugin has its own then, onFail, and onEither methods, which allow you to chain and connect plugins in a more modular way. For example:

getMyKiroBalance.then(isGreaterThan1000);
isGreaterThen1000.then(sendAllKiroToBob);
isGreaterThen1000.onFail(sendAllKiroToAlice);

fct.startWith(getMyKiroBalance);

In this example, we first connect getMyKiroBalance to isGreaterThen1000, then separately connect isGreaterThen1000 to sendAllKiroToBob and sendAllKiroToAlice based on the validation result. Finally, we set getMyKiroBalance as the starting node using fct.startWith().

Visualization

It's crucial to maintain the correct order of execution in this code, as the output of getMyKiroBalance is used as input for subsequent nodes. Changing the order may lead to incorrect or unexpected results. Always ensure the proper sequence when using outputs from one node as inputs for others.

4. Compile the graph

Finally, compile the graph to generate a transaction object:

const tx = fct.compile();

🎉 Congrats on successfully creating your FCT! Now you can proceed with executing the transaction or using it in your application as needed.