How to change evm token decimals?

Question

native token of my chain has 12 decimals,now i have integrated EVM functionality into my chain, is there any way by which i can change evm decimals from 18 to 12 as i don't want to change my native token decimals???

Answer 1

You should, and I recommend changing your native token decimals. Otherwise, you need a converter.

Then, I have a question.

Why do you need EVM? This will break almost every existing thing (such as smart contract). EVM's goal is to mock Ethereum and re-use the existing infrastructures. And the third-party developers will be so confused while developing base on your chain.

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Here https://github.com/darwinia-network/darwinia-common/blob/6a9392cfb9fe2c99b1c2b47d0c36125d61991bb7/frame/dvm/ethereum/src/adapter.rs#L136.

Darwinia has been running for over 2 years. Finally, we give up on maintaining this. We change the decimal to 18. So, that's my suggestion.

Answer 2

In order to change the decimals of your native token you have to modify your chain_spec.rs file. Import in the node/Cargo.toml sc-chain-spec

[dependencies.sc-chain-spec] 
branch = 'master'
git = "https://github.com/paritytech/substrate"

And in the function development_config() or local_testnet_config() add your properties:

let mut properties = sc_chain_spec::Properties::new();
properties.insert("tokenDecimals".into(), 12.into());

And finally add in properties: of the from_genesis call:

// Properties
Some(properties), 

See an example in the Parachain Template Node