Kutt/server/utils/index.ts

import ms from "ms";
import {
  differenceInDays,
  differenceInHours,
  differenceInMonths
} from "date-fns";
import generate from "nanoid/generate";
import { findLinkQuery } from "../queries/link";

export class CustomError extends Error {
  public statusCode?: number;
  public data?: any;
  public constructor(message: string, statusCode = 500, data?: any) {
    super(message);
    this.name = this.constructor.name;
    this.statusCode = statusCode;
    this.data = data;
  }
}

export const generateId = async (domainId: number = null) => {
  const address = generate(
    "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890",
    Number(process.env.LINK_LENGTH) || 6
  );
  const link = await findLinkQuery({ address, domainId });
  if (!link) return address;
  return generateId(domainId);
};

export const addProtocol = (url: string): string => {
  const hasProtocol = /^\w+:\/\//.test(url);
  return hasProtocol ? url : `http://${url}`;
};

export const generateShortLink = (id: string, domain?: string): string => {
  const protocol =
    process.env.CUSTOM_DOMAIN_USE_HTTPS === "true" || !domain
      ? "https://"
      : "http://";
  return `${protocol}${domain || process.env.DEFAULT_DOMAIN}/${id}`;
};

export const isAdmin = (email: string): boolean =>
  process.env.ADMIN_EMAILS.split(",")
    .map(e => e.trim())
    .includes(email);

export const getRedisKey = {
  link: (address: string, domain_id?: number, user_id?: number) =>
    `${address}-${domain_id || ""}-${user_id || ""}`,
  domain: (address: string) => `d-${address}`,
  host: (address: string) => `h-${address}`,
  user: (emailOrKey: string) => `u-${emailOrKey}`
};

// TODO: Add statsLimit
export const getStatsLimit = (): number =>
  Number(process.env.DEFAULT_MAX_STATS_PER_LINK) || 100000000;

export const getStatsCacheTime = (total?: number): number => {
  let durationInMs;
  switch (true) {
    case total <= 5000:
      durationInMs = ms("5 minutes");
      break;
    case total > 5000 && total < 20000:
      durationInMs = ms("10 minutes");
      break;
    case total < 40000:
      durationInMs = ms("15 minutes");
      break;
    case total > 40000:
      durationInMs = ms("30 minutes");
      break;
    default:
      durationInMs = ms("5 minutes");
  }
  return durationInMs / 1000;
};

export const statsObjectToArray = (obj: Stats) => {
  const objToArr = key =>
    Array.from(Object.keys(obj[key]))
      .map(name => ({
        name,
        value: obj[key][name]
      }))
      .sort((a, b) => b.value - a.value);

  return {
    browser: objToArr("browser"),
    os: objToArr("os"),
    country: objToArr("country"),
    referrer: objToArr("referrer")
  };
};

export const getDifferenceFunction = (
  type: "lastDay" | "lastWeek" | "lastMonth" | "allTime"
): Function => {
  if (type === "lastDay") return differenceInHours;
  if (type === "lastWeek") return differenceInDays;
  if (type === "lastMonth") return differenceInDays;
  if (type === "allTime") return differenceInMonths;
  throw new Error("Unknown type.");
};

export const getUTCDate = (dateString?: Date) => {
  const date = new Date(dateString || Date.now());
  return new Date(
    date.getUTCFullYear(),
    date.getUTCMonth(),
    date.getUTCDate(),
    date.getUTCHours()
  );
};