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type Nothing = null;
type Just<T> = T;
type NothingOrJust<T> = Nothing | Just<T>;
type NullOr<T> = T | null;
type NullOrUndefinedOr<T> = NullOr<T> | undefined;
// type PromiseNullOr<T> = Promise<NullOr<T>>;
// type ErrorOr<T> = Error | T;
// type PromiseErrorOr<T> = Promise<ErrorOr<T>>;
type TMapCallback<T, K> = (value: T) => K;
type TMapAsyncCallback<T, K> = (value: T) => Promise<K>;
// type TCallback<T> = (value: T) => never;
type TWarpCallback<T> = () => NullOrUndefinedOr<T>;type TWarpAsyncCallback<T> = () => Promise<NullOrUndefinedOr<T>>;
interface IMaybe<T> {  readonly _traceId: string;  readonly _value: NullOr<T>;}
abstract class AMaybe<T> implements IMaybe<T> {  abstract _traceId: string;  abstract _value: NullOr<T>;  abstract isSomething: boolean;  abstract isNothing: boolean;  abstract map<K>(cb: TMapCallback<T, K>): AMaybe<K>;  abstract amap<K>(cb: TMapAsyncCallback<T, K>): TMaybePromise<K>;  abstract extract(): NullOr<T>;}
type TMaybePromise<T> = Promise<AMaybe<T>>;
export class Maybe<T> implements AMaybe<T> {  _traceId: string;  _value: NullOr<T>;
  constructor(val: NullOrUndefinedOr<T>, traceId: string = "") {    this._traceId = traceId || Math.random().toString();    this._value = val === undefined ? null : val;  }
  public get isSomething(): boolean {    return this._value !== null;  }
  public get isNothing(): boolean {    return this._value === null;  }
  public map<K>(cb: TMapCallback<T, K>): AMaybe<K> {    if (this._value == null) {      return new Maybe<K>(null, this._traceId);    }
    try {      return new Maybe<K>(cb(this._value), this._traceId);    } catch (e: unknown) {      console.error(e);      return new Maybe<K>(null, this._traceId);    }  }
  public async amap<K>(cb: TMapAsyncCallback<T, K>): TMaybePromise<K> {    if (this._value == null) {      return new Maybe<K>(null, this._traceId);    }
    try {      return new Maybe<K>(await cb(this._value), this._traceId);    } catch (e: unknown) {      console.error(e);      return new Maybe<K>(null, this._traceId);    }  }
  public extract(): NullOr<T> {    return this._value;  }
  static is<X>(val: NullOrUndefinedOr<X>): Maybe<X> {    return new Maybe<X>(val);  }
  static wrap<T>(cb: TWarpCallback<T>): AMaybe<T> {    try {      return Maybe.is<T>(cb());    } catch (e: unknown) {      console.error(e);      return Maybe.is<T>(null);    }  }
  static async awrap<T>(cb: TWarpAsyncCallback<T>): TMaybePromise<T> {    try {      return Maybe.is<T>(await cb());    } catch (e: unknown) {      console.error(e);      return Maybe.is<T>(null);    }  }}