External Plugin

This is a third-party plugin. Please report issues in its Github Repository(opens new window)

# hardhat-typechain

Zero-config Typechain support

Updated for Hardhat!

Now supports Ethers v5 and Truffle v5!

Updated for TypeChain v3!

Add Typechain(opens new window) tasks to your hardhat project!

# What

TypeChain(opens new window) 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-v5 @typechain/truffle-v5 @typechain/web3-v1

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

require("hardhat-typechain");

Or, if you are using TypeScript, add this to your hardhat.config.ts:

import "hardhat-typechain";

# Zero Config Usage

Run the compile task as normal, and Typechain artifacts will automatically be generated in a root directory called typechain. Further configuration options are detailed below.

# Tasks

This plugin overrides the compile task and automatically generates new Typechain artifacts on each compilation.

There is an optional flag --no-typechain which can be passed in to skip Typechain compilation.

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(opens new window) (defaults to ethers).

This is an example of how to set it:

module.exports = {
  typechain: {
    outDir: "src/types",
    target: "ethers-v5",
  },
};

# Usage

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

Example Waffle + Ethers test that uses typedefs for contracts:

import { ethers, waffle } from "@nomiclabs/hardhat";
import chai from "chai";
import { Wallet } from "ethers";

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

const { deployContract } = waffle;
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(opens new window) for a full example!