```ts
export function parseSemver(version: string): { major: number; minor: number; patch: number; prerelease: string | null; build: string | null } {
    const regex = /^(\d{1,}\.\d{1,}\.\d{1,})(?:-([a-zA-Z0-9.-]+))?(?:\+([a-zA-Z0-9.-]+))?$/;
    const match = version.match(regex);

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

    const [, majorStr, minorStr, patchStr, prerelease, build] = match;

    const major = parseInt(majorStr, 10);
    const minor = parseInt(minorStr, 10);
    const patch = parseInt(patchStr, 10);

    return {
        major,
        minor,
        patch,
        prerelease: prerelease || null,
        build: build || null
    };
}
```