'namedAccounts' does not exist in type 'HardhatUserConfig'

Question

Unable to add 'namedAccounts' to 'HardhatUserConfig' in hardhat.config.ts as it throws below compilation error.

'namedAccounts' does not exist in type 'HardhatUserConfig'

Below is my config file :

import "@nomiclabs/hardhat-etherscan";
import "hardhat-gas-reporter";
import * as dotenv from 'dotenv';
import { HardhatUserConfig } from "hardhat/config"
dotenv.config();

const RINKEBY_RPC_URL = process.env.RINKEBY_RPC_URL || "";
const PRIVATE_KEY = process.env.PRIVATE_KEY || "";
const ETHERSCAN_APIKEY = process.env.ETHERSCAN_APIKEY;
const GOERLI_RPC_URL = process.env.GOERLI_RPC_URL || "";

const config: HardhatUserConfig = {
  solidity: "0.8.7",
  defaultNetwork: "hardhat",
  networks: {
    rinkeby: {      
      url: RINKEBY_RPC_URL,
      accounts: [PRIVATE_KEY],
      chainId: 4
    },     
    goerli: {
      url: GOERLI_RPC_URL,
      accounts: [PRIVATE_KEY],
      chainId: 5
    },
    localhost: {
      url: 'http://127.0.0.1:8545/',
      chainId: 31337      
    },   
  },
  etherscan: {
    apiKey: ETHERSCAN_APIKEY
  },
  gasReporter: {
    enabled: true,
    outputFile: "gas-report.txt",
    noColors: true    
  },
  //This throws error
  namedAccounts: {
    deployer: {
      default: 0
    },
    player: {
      default: 1
    }
  },
}

export default config;

These are the package version's I'm using.

{
  "name": "sample-project",
  "devDependencies": {
    "@nomiclabs/hardhat-ethers": "npm:hardhat-deploy-ethers@^0.3.0-beta.13",
    "@nomiclabs/hardhat-etherscan": "^3.1.0",
    "@typechain/ethers-v5": "^10.1.0",
    "@typechain/hardhat": "^6.1.2",
    "@types/chai": "^4.3.3",
    "@types/node": "^18.7.15",
    "chai": "^4.3.6",
    "dotenv": "^16.0.2",
    "ethereum-waffle": "^3.4.4",
    "ethers": "^5.7.0",
    "hardhat": "^2.11.0",
    "hardhat-contract-sizer": "^2.6.1",
    "hardhat-deploy": "^0.11.13",
    "hardhat-gas-reporter": "^1.0.9",
    "prettier": "^2.7.1",
    "prettier-plugin-solidity": "^1.0.0-beta.24",
    "solhint": "^3.3.7",
    "solidity-coverage": "^0.8.0",
    "ts-node": "^10.9.1",
    "typechain": "^8.1.0",
    "typescript": "^4.8.2"
  },
  "dependencies": {
    "@chainlink/contracts": "^0.4.1"
  }
}

Answer 1

You need to import hardhat-deploy in order for the config type to be extended.

Example (es6):

import { HardhatUserConfig } from "hardhat/config";
import "hardhat-deploy"; // add this line

const config: HardhatUserConfig = {
  solidity: "0.8.9",
  namedAccounts: {
    deployer: { default: 0 },
  },
};

export default config;

See an example project with a complex config here.