```typescript
export function parseSemver(version: string): { major: number; minor: number; patch: number; prerelease: string | null; build: string | null } {
    const regex = /^(0|[1-9]\d*)\.(0|[1-9]\d*)\.(0|[1-9]\d*)(?:-(pre|beta|alpha)\.\d+)?(?:\+(\w+))?$/;
    const match = version.match(regex);

    if (!match) {
        throw new Error(`Invalid semantic version string: ${version}`);
    }

    return {
        major: parseInt(match[1], 10),
        minor: parseInt(match[2], 10),
        patch: parseInt(match[3], 10),
        prerelease: match[4] ? `${match[4]}-${match[5]}` : null,
        build: match[6] !== undefined ? match[6] : null
    };
}
```