utils.ts

/** Obfuscate-mail option */
export interface Options {
  /** Specify how long the asterisks `*` length would be */
  asterisksLength: number;
  /** Set the minimum obfuscated mail length */
  minimumLength: number;
  /** Visible Characters options */
  visibleCharacters: {
    /** Expand the visible characters. On the first part */
    startLength: number;
    /** Expand the visible characters. On the middle part */
    middleLength: number;
    /** Expand the visible characters. On the last part */
    endLength: number;
  };
  /** Show domain name? (those `*@example.*`) */
  showDomainName: boolean;
  /** Show domain extension? (those `*@*.com`) */
  showDomainExtension: boolean;
  /** The fallback if the provided email isnt valid */
  invalidEmailValue: string;
}
/** Undefined value */
export type Undef = null | undefined;
function undef<T extends unknown>(value: T): boolean {
  return typeof value === 'undefined' || value === null;
}
/** Make every objects Null-ish */
export type Nullish<T> =
  | { [K in keyof T]+?: T[K] extends object ? Nullish<T[K]> : T[K]}
  | Undef;
function getOptionsProto<T extends object>(
  options: Nullish<T>,
  def: T,
  fromDes?: string,
): T {
  const res: T = def;
  if (!options || Object.keys(options).length < 1) {
    return res;
  }
  for (const [_k, v] of Object.entries(options!)) {
    // typescript dosent resolve types on RT, only CT
    if (undef(v)) {
      continue;
    }
    const resDyn = res as { [key: string]: T[keyof T] };
    if (
      typeof resDyn[_k] !== typeof v ||
      (resDyn[_k] instanceof Array) !== (v instanceof Array)
    ) {
      throw new TypeError(
        `Object ${
          fromDes ? `${fromDes}.` : ''
        }${_k} type needs to be same as Options.${
          fromDes ? `${fromDes}.` : ''
        }${_k}`,
      );
    }
    const k: keyof T = _k as keyof T;
    if (typeof v === 'object' && !(v instanceof Array)) {
      type Nested = T[typeof k] extends Record<string, unknown> ? T[typeof k]
        : never;
      res[k] = getOptionsProto<Nested>(
        v,
        res[k] as Nested,
        fromDes ? `${fromDes}.${String(k)}` : String(k),
      );
    } else {
      res[k] = v as T[keyof T];
    }
  }
  return res;
}
/**
 * @param {Options} options
 * @returns {Options}
 */
export function getOptions(options: Nullish<Options>): Options {
  return getOptionsProto<Options>(options, DEFAULT_OPTIONS);
}
/** Default options **/
export const DEFAULT_OPTIONS: Options = {
  asterisksLength: 6,
  minimumLength: 4,
  visibleCharacters: {
    startLength: 3,
    middleLength: 2,
    endLength: 2,
  },
  showDomainName: false,
  showDomainExtension: true,
  invalidEmailValue: '*********@****.**',
};