#Migrating from Waffle

This page explains how to migrate from Waffle to Hardhat Chai Matchers, and the advantages of doing it. Migrating should only take a few minutes.

# How to migrate

The @nomicfoundation/hardhat-chai-matchers plugin is meant to be a drop-in replacement for the @nomiclabs/hardhat-waffle plugin. To migrate, follow these instructions:

1. Uninstall the @nomiclabs/hardhat-waffle and ethereum-waffle packages:

   npm 7+

   npm 6

   yarn

   npm uninstall @nomiclabs/hardhat-waffle ethereum-waffle
   

   npm uninstall @nomiclabs/hardhat-waffle ethereum-waffle
   

   yarn remove @nomiclabs/hardhat-waffle ethereum-waffle
   

2. Then install the Hardhat Chai Matchers plugin:

   npm 7+

   npm 6

   yarn

   npm install --save-dev @nomicfoundation/hardhat-chai-matchers
   

   npm install --save-dev @nomicfoundation/hardhat-chai-matchers
   

   yarn add --dev @nomicfoundation/hardhat-chai-matchers
   

3. In your Hardhat config, import the Hardhat Chai Matchers plugin and remove the hardhat-waffle one:

   TypeScript

   JavaScript

   - import "@nomiclabs/hardhat-waffle";
   + import "@nomicfoundation/hardhat-chai-matchers";
   

   - require("@nomiclabs/hardhat-waffle");
   + require("@nomicfoundation/hardhat-chai-matchers");
   

4. If you were not importing the @nomiclabs/hardhat-ethers plugin explicitly (because the Hardhat Waffle plugin already imported it), then add it to your config:

   TypeScript

   JavaScript

   import "@nomiclabs/hardhat-ethers";
   

   require("@nomiclabs/hardhat-ethers");
   

# Why migrate?

The Hardhat Chai Matchers are compatible with Waffle's API and offer several advantages:

• More features: the Hardhat Chai Matchers include new matchers, like .revertedWithCustomError and .revertedWithPanic, which let you perform better assertions of a transaction's revert reason.
• Support for native BigInts: Besides numbers and ethers’s BigNumbers, you can also use JavaScript's native BigInts in your assertions, which means being able to do things like expect(await token.totalSupply()).to.equal(10n**18n) instead of expect(await token.totalSupply()).to.equal(ethers.BigNumber.from("1000000000000000000")).
• More reliable: Several problems and minor bugs in Waffle's matchers are fixed in the Hardhat Chai Matchers.