Angelmaneuver/unit-converter

import * as Types from "./type";

export class Optional<T> {
    private value: Types.Nullable<T>;

    constructor(value: Types.Nullable<T>) {
        this.value = value;
    }

    public static empty<T>(): Optional<T> {
        return new Optional<T>(null);
    }

    public static ofNullable<T>(value: Types.Nullable<T>): Optional<T> {
        return new Optional<T>(value);
    }

    public isPresent(): boolean {
        return this.value !== null && this.value !== undefined ? true : false;
    }

    public orElseNonNullable(other: NonNullable<T>): NonNullable<T> {
        return (this.value !== null && this.value !== undefined ? this.value : other) as NonNullable<T>;
    }

    public orElseThrow(error: Error): NonNullable<T> {
        if (this.value !== null && this.value !== undefined) {
            return this.value as NonNullable<T>;
        } else {
            throw error;
        }
    }
}