hardhat-typechain

Updated for Hardhat!

Now supports Ethers v5 and Truffle v5!

Updated for TypeChain v2!

Add Typechain tasks to your hardhat 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 hardhat-typechain typechain ts-generator
# choose plugin for required target, only need to install one of these
npm i @typechain/ethers-v4 @typechain/ethers-v5 @typechain/truffle-v5 @typechain/web3-v1 @typechain/truffle-v4

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

usePlugin("hardhat-typechain");

Tasks

This plugin adds the typechain task to hardhat:

Generate Typechain typings for compiled contracts

Configuration

This plugin extends the hardhatConfig 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-v5",
  },
};

Usage

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

Example Waffle + Ethers test that uses typedefs for contracts:

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

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

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

describe("Counter", () => {
  let counter: Counter;

  beforeEach(async () => {
    // 1
    const signers = await ethers.signers();

    // 2
    counter = (await deployContract(
      <Wallet>signers[0],
      CounterArtifact
    )) as Counter;
    const initialCount = await counter.getCount();

    // 3
    expect(initialCount).to.eq(0);
    expect(counter.address).to.properAddress;
  });

  // 4
  describe("count up", async () => {
    it("should count up", async () => {
      await counter.countUp();
      let count = await counter.getCount();
      expect(count).to.eq(1);
    });
  });

  describe("count down", async () => {
    // 5
    it("should fail", async () => {
      await counter.countDown();
    });

    it("should count down", async () => {
      await counter.countUp();

      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/hardhat-typechain/src/type-extensions.d.ts"