Documentation Index
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License
Type-safe SPDX license identifiers for smart contract metadata.
Overview
Branded string type representing SPDX license identifiers. Used in Solidity source files and smart contract metadata to identify licensing terms. Includes validation for OSI-approved licenses.
Quick Start
Basic Usage
Common Licenses
Solidity Usage
import * as License from '@tevm/voltaire/License'
// Create license identifier
const mit = License.from("MIT")
const apache = License.from("Apache-2.0")
const unlicensed = License.from("UNLICENSED")
// Convert to string
License.toString(mit) // "MIT"
// Check OSI approval
License.isOSI("MIT") // true
License.isOSI("Apache-2.0") // true
License.isOSI("UNLICENSED") // false
import { COMMON_LICENSES, OSI_APPROVED_LICENSES } from '@tevm/voltaire/License'
// Common SPDX identifiers
COMMON_LICENSES
// ["MIT", "Apache-2.0", "GPL-3.0", "GPL-2.0", "LGPL-3.0",
// "BSD-3-Clause", "BSD-2-Clause", "ISC", "MPL-2.0", "UNLICENSED"]
// OSI-approved licenses
OSI_APPROVED_LICENSES
// ["MIT", "Apache-2.0", "GPL-3.0", "GPL-2.0", "LGPL-3.0",
// "LGPL-2.1", "BSD-3-Clause", "BSD-2-Clause", "ISC",
// "MPL-2.0", "AGPL-3.0", "EPL-2.0", "CC0-1.0"]
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
contract MyContract {
// Contract code
}
import * as License from '@tevm/voltaire/License'
// Parse license from Solidity source
const source = `// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;`
const match = source.match(/SPDX-License-Identifier:\s*(\S+)/)
if (match) {
const license = License.from(match[1])
console.log(License.isOSI(license)) // true
}
Common Licenses
| License | OSI Approved | Description |
|---|
| MIT | Yes | Permissive, minimal restrictions |
| Apache-2.0 | Yes | Permissive with patent grant |
| GPL-3.0 | Yes | Strong copyleft |
| GPL-2.0 | Yes | Strong copyleft (earlier version) |
| LGPL-3.0 | Yes | Weak copyleft for libraries |
| BSD-3-Clause | Yes | Permissive with attribution |
| BSD-2-Clause | Yes | Simplified BSD |
| ISC | Yes | Simplified BSD-like |
| MPL-2.0 | Yes | Weak copyleft file-level |
| AGPL-3.0 | Yes | Strong copyleft + network use |
| UNLICENSED | No | Proprietary/no license |
API Reference
Constructors
import * as License from '@tevm/voltaire/License'
// Create from SPDX identifier
const license = License.from("MIT")
Methods
import * as License from '@tevm/voltaire/License'
const license = License.from("Apache-2.0")
// Convert to string
License.toString(license) // "Apache-2.0"
// Check if OSI-approved
License.isOSI(license) // true
License.isOSI("GPL-3.0") // true
License.isOSI("UNLICENSED") // false
Constants
import { COMMON_LICENSES, OSI_APPROVED_LICENSES } from '@tevm/voltaire/License'
// Common SPDX license identifiers
COMMON_LICENSES: string[]
// OSI-approved open source licenses
OSI_APPROVED_LICENSES: string[]
Solidity License Identifier
SPDX license identifiers are required in Solidity files since version 0.6.8:
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
- Identify licensing terms programmatically
- Filter contracts by license type
- Ensure compliance with open source requirements
Use Cases
import * as License from '@tevm/voltaire/License'
interface ContractMetadata {
license: string
compiler: string
source: string
}
function analyzeContract(metadata: ContractMetadata) {
const license = License.from(metadata.license)
return {
license: License.toString(license),
isOpenSource: License.isOSI(license),
isPermissive: ["MIT", "Apache-2.0", "BSD-3-Clause"].includes(
License.toString(license)
)
}
}
License Filtering
import * as License from '@tevm/voltaire/License'
import { OSI_APPROVED_LICENSES } from '@tevm/voltaire/License'
interface Contract {
address: string
license: string
}
function filterOpenSourceContracts(contracts: Contract[]): Contract[] {
return contracts.filter(c => License.isOSI(c.license))
}
function filterByLicense(contracts: Contract[], allowed: string[]): Contract[] {
return contracts.filter(c => allowed.includes(c.license))
}
// Only permissive licenses
const permissive = filterByLicense(contracts, ["MIT", "Apache-2.0", "BSD-3-Clause"])
References
