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import { Value } from './Value.ts';
export abstract class EnvValue<T> {  readonly #key: string;
  readonly #rawValue: string | undefined;
  readonly #defaultValue: Value<T> | null;
  #computedValue: Value<T> | null = null;
  constructor(key: string, defaultValue?: T) {    this.#key = key;    this.#rawValue = Deno.env.get(key);    this.#defaultValue =      defaultValue === undefined ? null : new Value(defaultValue);  }
  protected abstract mapper(rawValue: string): T;
  private compute() {    if (this.#rawValue) {      return this.mapper(this.#rawValue);    } else if (this.#defaultValue !== null) {      return this.#defaultValue.get();    } else {      throw new Error(`Env variable ${this.#key} is not defined`);    }  }
  public get() {    return (this.#computedValue      ? this.#computedValue      : (this.#computedValue = new Value(this.compute()))    ).get();  }}