display.ts

// Copyright 2023-present the Deno authors. All rights reserved. MIT license.
import { difference, type Unit } from "std/datetime/difference.ts";

/**
 * Returns a pluralized string for the given amount and unit.
 *
 * @example
 * ```ts
 * import { pluralize } from "@/utils/display.ts";
 *
 * pluralize(0, "meow"); // Returns "0 meows"
 * pluralize(1, "meow"); // Returns "1 meow"
 * ```
 */
export function pluralize(amount: number, unit: string) {
  // return amount === 1 ? `${amount} ${unit}` : `${amount} ${unit}s`;
  return `${amount} ${unit}`;
}

/**
 * Returns how long ago a given date is from now.
 *
 * @example
 * ```ts
 * import { timeAgo } from "@/utils/display.ts";
 * import { SECOND, MINUTE, HOUR } from "std/datetime/constants.ts";
 *
 * timeAgo(new Date()); // Returns "just now"
 * timeAgo(new Date(Date.now() - 3 * HOUR)); // Returns "3 hours ago"
 * ```
 */
export function timeAgo(date: Date) {
  const now = new Date();

  if (date > now) {
    throw new Error("Timestamp must be in the past");
  }

  const match = Object.entries(
    difference(now, date, {
      // These units make sense for a web UI
      units: [
        "seconds",
        "minutes",
        "hours",
        "days",
        "weeks",
        "months",
        "years",
      ],
    }),
  )
    .toReversed()
    .find(([_, amount]) => amount > 0);

  if (match === undefined) {
    return "şimdi";
  }

  const [unit, amount] = match;

  const unitMapping: Record<Unit, string> = {
    milliseconds: "milisaniye",
    seconds: "saniye",
    minutes: "dakika",
    hours: "saat",
    days: "gün",
    weeks: "hafta",
    months: "ay",
    quarters: "çeyrek",
    years: "yıl",
  };

  return `${pluralize(amount, unitMapping[<Unit> unit])} önce`;
}

/**
 * Returns a formatted string based on the given amount of currency and the
 * `en-US` locale. Change the locale for your use case as required.
 *
 * @see {@linkcode Intl.NumberFormat}
 *
 * @example
 * ```ts
 * import { formatCurrency } from "@/utils/display.ts";
 *
 * formatCurrency(5, "USD"); // Returns "$5"
 * ```
 */
export function formatCurrency(
  amount: number,
  currency: string,
): string {
  return new Intl.NumberFormat(
    "en-US",
    {
      style: "currency",
      currency,
      currencyDisplay: "symbol",
      maximumFractionDigits: 0,
    },
  ).format(amount)
    // Issue: https://stackoverflow.com/questions/44533919/space-after-symbol-with-js-intl
    .replace(/^(\D+)/, "$1")
    .replace(/\s+/, "");
}