buidler

buidler-typechain

Add Typechain tasks to your Buidler project!

What

TypeChain gives you Typescript bindings for your smart contracts. Now, your tests and frontend code can be typesafe and magically autocomplete smart contract function names!

Installation

npm i buidler-typechain typechain ts-generator typechain-target-ethers typechain-target-truffle typechain-target-web3-v1

And add the following statement to your buidler.config.js:

usePlugin("buidler-typechain);

Tasks

This plugin adds the typechain task to Buidler:

Generate Typechain typings for compiled contracts

Configuration

This plugin extends the BuidlerConfig optional typechain object. The object contains two fields, outDir and target. outDir is the output directory of the artifacts that TypeChain creates (defaults to typechain). target is one of the targets specified by the TypeChain docs (defaults to ethers).

This is an example of how to set it:

module.exports = {
  typechain: {
    outDir: "src/types",
    target: "ethers"
  }
};

Usage

npx buidler typechain - Compiles and generates Typescript typings for your contracts.

Example Waffle + Ethers test that uses typedefs for contracts:

import { ethers } from "@nomiclabs/buidler";
import chai from "chai";
import { deployContract, getWallets, solidity } from "ethereum-waffle";

import CounterArtifact from "../build/Counter.json";
import { Counter } from "../typechain/Counter"

chai.use(solidity);
const { expect } = chai;

describe("Counter", () => {
  const provider = ethers.provider;
  let [wallet] = getWallets(provider);

  // use contract type
  let counter: Counter;

  beforeEach(async () => {
    // cast as type
    counter = await deployContract(wallet, CounterArtifact) as Counter;

    // function name is available as part of types
    const initialCount = await counter.getCount();

    expect(initialCount).to.eq(0);
    expect(counter.address).to.properAddress;
  });

  it("should count up", async () => {
    await counter.countUp();
    let count = await counter.getCount();
    expect(count).to.eq(1);

    await counter.countUp();
    count = await counter.getCount();
    expect(count).to.eq(2);
  });

  it("should count down", async () => {
    await counter.countDown();
    const count = await counter.getCount();
    expect(count).to.eq(0);
  });
});

See this starter kit for a full example!

TypeScript support

You need to add this to your tsconfig.json's files array: "node_modules/buidler-typechain/src/type-extensions.d.ts"