Accelerating Search Operations by Indexing Arrays with Map Instances

interface UserRecord {
  id: number;
  email: string;
}
 
class UserIndex {
  private indexMap = new Map<number, UserRecord>();
 
  constructor(records: UserRecord[]) {
    for (const record of records) {
      this.indexMap.set(record.id, record);
    }
  }
 
  public findById(id: number): UserRecord | undefined {
    return this.indexMap.get(id);
  }
}