SyntaxError: Unexpected token '?' in upgrading smart contract using #openzeppelin/hardhat-upgrades - blockchain

Question

I am trying to deploy an upgradable smart contract on polygon Mumbai tesnet. I am getting this error
smart-contract/node_modules/#openzeppelin/hardhat-upgrades/dist/index.js:108
compiler.settings ?? (compiler.settings = {});
^
SyntaxError: Unexpected token '?'
at wrapSafe (internal/modules/cjs/loader.js:915:16)
at Module._compile (internal/modules/cjs/loader.js:963:27)
at Module._extensions..js (internal/modules/cjs/loader.js:1027:10)
at Object.require.extensions.<computed> [as .js] (/Users/jagdish/workspace/speedrun-simple-nft-example/smart-contract/node_modules/ts-node/src/index.ts:1587:43)
at Module.load (internal/modules/cjs/loader.js:863:32)
at Function.Module._load (internal/modules/cjs/loader.js:708:14)
at Module.require (internal/modules/cjs/loader.js:887:19)
at require (internal/modules/cjs/helpers.js:74:18)
at Object.<anonymous> (/Users/jagdish/workspace/speedrun-simple-nft-example/smart-contract/hardhat.config.ts:4:1)
at Module._compile (internal/modules/cjs/loader.js:999:30)
while trying to run the deploy script.
here are my configs and deploy scripts:
hardhart.config.ts
import { task } from "hardhat/config";
// import "#nomiclabs/hardhat-waffle";
import 'hardhat-watcher';
import '#openzeppelin/hardhat-upgrades';
import '#nomiclabs/hardhat-ethers';
import dotenv from "dotenv"
dotenv.config()
// This is a sample Hardhat task. To learn how to create your own go to
// https://hardhat.org/guides/create-task.html
task("accounts", "Prints the list of accounts", async (taskArgs, hre) => {
const accounts = await hre.ethers.getSigners();
for (const account of accounts) {
console.log(account.address);
}
});
// You need to export an object to set up your config
// Go to https://hardhat.org/config/ to learn more
/**
* #type import('hardhat/config').HardhatUserConfig
*/
module.exports = {
solidity: "0.8.4",
watcher: {
compilation: {
tasks: ['compile'],
},
node: {
tasks: ['node'],
},
},
networks: {
matic: {
url: "https://polygon-rpc.com/",
accounts: [process.env.ACCOUNT_PRIVATE_KEY]
},
matic_mumbai: {
url: "https://rpc-mumbai.maticvigil.com",
accounts: [process.env.ACCOUNT_PRIVATE_KEY]
}
}
};
deploy.ts
import { ethers, upgrades } from "hardhat";
async function main() {
const contract = await ethers.getContractFactory("YourCollectible");
console.log("Deploying Contract ...");
const c = await upgrades.deployProxy(contract, { constructorArgs: ["Your Collectables", "YCB"] })
// const c = await contract.deploy("Your Collectable", "YCB");
await c.deployed();
console.log("Contract deployed to:", c.address);
}
main()
.then(() => process.exit(0))
.catch((error) => {
console.error(error);
process.exit(1);
});
package.json
{
"name": "smart-contract",
"version": "1.0.0",
"description": "",
"main": "index.js",
"scripts": {
"run": "hardhat compile",
"test": "echo \"Error: no test specified\" && exit 1"
},
"keywords": [],
"author": "",
"license": "ISC",
"devDependencies": {
"#nomiclabs/hardhat-ethers": "^2.0.6",
"#nomiclabs/hardhat-waffle": "^2.0.3",
"#openzeppelin/hardhat-upgrades": "^1.20.0",
"#typechain/hardhat": "^6.1.2",
"chai": "^4.3.6",
"ethereum-waffle": "^3.4.4",
"ethers": "^5.6.9",
"hardhat": "^2.9.9",
"hardhat-watcher": "^2.3.0",
"ts-node": "^10.8.1",
"typescript": "^4.7.4"
},
"dependencies": {
"#openzeppelin/contracts": "^4.7.0",
"dotenv": "^16.0.1"
}
}
I am not sure whether it is the node version issue in my local or do I have to downgrade the #openzeppelin/hardhat-upgrades version (I have tried that).
Node version: v12.22.10
Can anyone help on this

Answer 1

I had the same problem with node 12. Problem solved after updating to node 16 and running yarn again.