Solution for [INTERMEDIATE CHALLENGE] Smart contracts - write an ERC-20 smart contract with ink!

NukeManDan

Node

See the substrate-node-template folder for the edits made to have the contracts pallet added

ERC20 contract in ink!

Derived from the examples directly, see the erc20 folder for the /target/* files with the compiled wasm and metadata needed.

Front End

See the substrate-front-end-template folder for edits made to interact with the deployed ERC20 contract.

Instructions to deploy and create and instance of the ERC20 contract

• Compile the node
• Open up the Canvas UI

• Follow instructions from this tutorial to upload the /erc20/target/erc20.wasm file and /erc20/target/erc20metadata.json ABI file.

• alternatively you can use the polkadot.js/apps interface
• Deploy a new contract with 1000000000 tokens from the Alice account.
• COPY THE DEPLOYED INSTANCE HASH/ADDR and replace the one in ERC20.js with this hash:

• >const addr = ''

The Deployed Contract Address should be: 5G7aVUF6RhN1QWtLY7VHa32fSFWaA1oLGuMrjvTLoqcpGqR7

• NOTE: this may vary, be sure to get this from the UI after you actually create an instance.

Transfer the ERC20 with Canvas UI

Using the Execute tab from the UI, use the Message to Send = transfer(to: AccountId, value: u128): Result<(), Error>) and send Bob 500 units.

Transfer the ERC20 with custom UI

Starting with a fresh chain (use ./target/release/node-template/purge-chain --dev -y ), redelpoy the contract, but this time with 1000000000 tokens. We want to send Bob 5000000 this time.

Be sure that you re-upload the contract via Canvas AND the hash is updated in ERC20.js!

See instructions in substrate-front-end-template to bring up the template. Then use the UI for the ERC20 to transfer funds!

Note that the ballances is non functional for the ERC20 at this time. It will not display.

You should see a valid event to ContractExecution! If you get a DispatchError (specifically index 9, error 12), check if the address of the deployed contact is correct!

Check the balances via the Canvas UI: