solc-js

0.8.28 verified Fri May 01 auth: no javascript

JavaScript bindings for the Solidity compiler (solc). Version 0.8.28 provides access to Solidity compilation via Node.js, using Emscripten-compiled binaries from solc-bin. It is released frequently, tracking Solidity releases. Key differentiators: it is the official JS wrapper for the Solidity compiler, supports both high-level (Standard JSON I/O) and low-level APIs, and provides a command-line tool (solcjs) for compilation. Unlike the native binary, it runs entirely in Node.js without additional dependencies.

Common errors

error Error: CompileError: Source file requires different compiler version (current compiler is 0.8.28+commit.8e4c6f11.Emscripten.clang) ↓

cause The Solidity source specifies a different pragma version than the compiler version installed.

fix

Update the pragma in your .sol file or install a compatible version of solc.

error Error: Cannot find module 'solc' ↓

cause The package is not installed or path is incorrect.

fix

Run 'npm install solc' in your project directory.

error TypeError: solc.compile is not a function ↓

cause Using ESM import ('import solc from 'solc'') instead of CommonJS require or incorrect version.

fix

Use 'const solc = require('solc');' and ensure you have the latest version installed.

Warnings

breaking Since version 0.6.0, compile() only accepts an object for callbacks, not individual callback functions. ↓

fix Pass an object with import and/or smtSolver properties instead of separate function arguments.

gotcha The command-line tool solcjs is not compatible with solc from the Solidity package; it cannot be used with eth.compile.solidity() RPC method. ↓

fix Use solcjs for standalone compilation; for Ethereum client integration, install the native solc binary.

gotcha Import callback must be synchronous; async file reads will not work. ↓

fix Use synchronous file reads (e.g., fs.readFileSync) or preload all dependencies before compiling.

deprecated compileStandardWrapper is deprecated in favor of compile() with an object callback (since 0.6.0). ↓

fix Use solc.compile(JSON.stringify(input), { import: ... }) instead.

Install

npm install scol

yarn add scol

pnpm add scol

Imports

solc
wrong
```
import solc from 'solc';
```
correct
```
const solc = require('solc');
```
The package does not provide ES module exports by default; use CommonJS require or configure your bundler to handle CJS.
compile
wrong
```
solc.compile(input)
```
correct
```
solc.compile(JSON.stringify(input))
```
The compile function expects a JSON string, not an object. You must stringify the input.
compileStandardWrapper
wrong
```
const output = solc.compile(input);
```
correct
```
const output = solc.compileStandardWrapper(JSON.stringify(input));
```
compileStandardWrapper is the recommended high-level API for versions >=0.6.0. It handles JSON parsing and stringification.

Quickstart

Compiles a simple Solidity contract using the high-level API and prints the bytecode.

const solc = require('solc');
const input = {
  language: 'Solidity',
  sources: {
    'test.sol': {
      content: '// SPDX-License-Identifier: MIT\npragma solidity ^0.8.0;\ncontract Test { }'
    }
  },
  settings: {
    outputSelection: {
      '*': {
        '*': ['evm.bytecode.object']
      }
    }
  }
};
const output = JSON.parse(solc.compile(JSON.stringify(input)));
console.log(output.contracts['test.sol'].Test.evm.bytecode.object);