const { merge } = require('sol-merger');

// Get the merged code as a string
const mergedCode = await merge("./contracts/MyContract.sol");
// Print it out or write it to a file etc.
console.log(mergedCode);

Right now it only works with solidity files that are in node_modules or relative to your solidity file.

Simple usage:

npm i --save-dev sol-merger

Then add following line to your package.json.

{
  "scripts": {
    "build-contracts": "sol-merger \"./contracts/*.sol\" ./build"
  },
}

This will allow you to use npm run build-contracts in your project directory.

Note that contracts glob should be surrounded with "

If no output file specified then output file will be created at the same directory and appended with _merged (by default), i.e. MyContract_merged.sol. You can also change this behaviour by specifying --append option:

sol-merger --append _me "./contracts/*.sol"
sol-merger -a _me "./contracts/*.sol"

You may need to use npm run to invoke the program standalone, as in npm run sol-merger.

You can also get help via --help command

sol-merger -h
sol-merger --help

More info about glob available at node-glob repository

See tests for more examples.

It is possible right now to write your own plugins to process exports. Currently state is not used in plugins. To see available plugins take a look plugins page.

All default plugins are available via shortcut syntax using filename:

sol-merger --export-plugin SPDXLicenseRemovePlugin "test/contracts/*.sol" compiled

It is also possible to use external plugins via relative path to plugin or path relative to node_modules:

sol-merger --export-plugin ./dist/lib/plugins/SPDXLicenseRemovePlugin.js "test/contracts/*.sol" compiled

sol-merger --export-plugin sol-merger/lib/plugins/SPDXLicenseRemovePlugin.js "test/contracts/*.sol" compiled

Note that file extension is required for plugin to be loaded.

It is possible to setup environment variable to see what is happening under the hood when contracts are being compiled:

export DEBUG="sol-merger*"

I created a plugin for VSCode so you can use it instead of sol-merger: Solidity Contracts Merger.

Hope you will like it.