ewasm-jsvm

1. ewasm virtual machine
2. evm virtual machine

UPDATE: the ewasm part is outdated and is currently being developed in another (private for now) repo. The EVM virtual machine can be used as a debugger (not efficient, as it offers a snapshot state of storage, memory and logs after each opcode).

Specs: https://github.com/ewasm/design/blob/master/eth_interface.md.

! Use it only for testing. Not production ready.

Use

Needs peer dependencies: npm install ethers --save.

npm install ewasm-jsvm --save

Node

For i64 support, use a Node.js version which supports the --experimental-wasm-bigint flag. E.g. v13.10.1

Browser

A limited (Ethereum interface methods with args of type i64 are not supported by browsers), but easier to use version of the ewasm-jsvm can be found at https://observablehq.com/@loredanacirstea/ewasmjsvm.

Development

cd ewasm-jsvm
yarn

Run Tests

npm run test

To test a contract:

• add the source in ./tests/contracts for Yul or ./tests/sol for Solidity
• in ./tests/jsvm.test.js:
  • add the abi, like

    ewasm-jsvm/tests/jsvm.test.js

    Lines 86 to 90 in 54c3599

    	const c10Abi = [
    	{ name: 'constructor', type: 'constructor', inputs: [], outputs: []},
    	{ name: 'sum', type: 'function', inputs: [{ name: 'a', type: 'uint256'}, { name: 'b', type: 'uint256'}], outputs: [{ name: 'c', type: 'uint256'}]},
    	{ name: 'double', type: 'function', inputs: [{ name: 'a', type: 'uint256'}], outputs: [{ name: 'b', type: 'uint256'}]},
    	]

  • write a new test

For contracts that only need to execute the constructor, check out the c1 contract, abi & test:

const ewmodule = ewasmjsvm.runtimeSim(contracts.c1.bin, c1Abi);
const answ = await ewmodule.main(DEFAULT_TX_INFO);

For contracts where the constructor returns a runtime wasm to be deployed (that only has a fallback/default function), check out c2 contract, abi & test:

const runtime = await ewasmjsvm.deploy(contracts.c2.bin, c2Abi)(DEFAULT_TX_INFO);
const answ = await runtime.main(DEFAULT_TX_INFO);

For contracts with functions, check out the c10 contract, abi & test:

const runtime = await ewasmjsvm.deploy(contracts.c10.bin, c10Abi)(DEFAULT_TX_INFO);
let answ = await runtime.sum(8, 2, DEFAULT_TX_INFO);