Here is how you can implement `parseSemver` function:

```ts
export function parseSemver(version: string): { major: number; minor: number; patch: number; prerelease: string | null; build: string | null } {
  const semverPattern = /^0*([1-9][0-9]*)\.0*([1-9][0-9]*)\.0*([1-9][0-9]*)(?:-(?<prerelease>[\da-z-]+(?:\.[\da-z-]+)*))?(?:\+(?<build>[\da-z-]+(?:\.[\da-z-]+)*))?$/i;
  const matches = semverPattern.exec(version);

  if (matches === null) {
    throw new Error('Invalid input');
  }

  return {
    major: parseInt(matches[1], 10),
    minor: parseInt(matches[2], 10),
    patch: parseInt(matches[3], 10),
    prerelease: matches.groups?.['prerelease'] || null,
    build: matches.groups?.['build'] || null,
  };
}
```