@ganache/console.log

@ganache/console.log

A Solidity library and EVM hooks for using console.log from Solidity contracts.

Usage:

@ganache/console.log was designed to be used with the @ethereumjs/vm npm package.

Install @ganache/console.log:

> npm install @ganache/console.log --save-exact

@ganache/console.log has two parts, a console.sol Solidity library file, and a method to capture logs generated by the use of the console.sol library.

console.sol Solidity Library

The console.sol library is available at @ganache/console.log/console.sol. There are various ways to make this file available to your contracts and Solidity build pipelines, so this part is left up to the user.

Use it in Solidity just like any other library, e.g.,

// SPDX-License-Identifier: MIT
pragma solidity >= 0.4.22 <0.9.0;

import "console.sol";

contract MyContract {
    constructor() {
        console.log("got here");
    }
}

console.log parser (maybeGetLogs):

To use @ganache/console.log directly within an instance of the @ethereumjs/vm VM:

import { ConsoleLogs, maybeGetLogs } from "@ganache/console.log";

// ... initialize vm ...

// vm should be an instance of @ethereumjs/vm
vm.evm.events.on("step", event => {
  const logs: ConsoleLogs | null = maybeGetLogs(event); // (string | bigint | boolean)[] | null
  // do something with `logs`
});

Note: Ganache CLI, as well as Ganache.server and Ganache.provider, already implement the logger parser and will automatically log calls to console.sol to standard output just like JavaScript's console.log.