advanced.js

import { FORMAT_DEFAULT } from "./constant.js";

export default (o, c, d) => {
  // locale needed later
  const proto = c.prototype;
  const oldFormat = proto.format;
  d.en.ordinal = (number) => {
    const s = ["th", "st", "nd", "rd"];
    const v = number % 100;
    return `[${number}${s[(v - 20) % 10] || s[v] || s[0]}]`;
  };
  // extend en locale here
  proto.format = function (formatStr) {
    const locale = this.$locale();

    if (!this.isValid()) {
      return oldFormat.bind(this)(formatStr);
    }

    const utils = this.$utils();
    const str = formatStr || FORMAT_DEFAULT;
    const result = str.replace(
      /\[([^\]]+)]|Q|wo|ww|w|WW|W|zzz|z|gggg|GGGG|Do|X|x|k{1,2}|S/g,
      (match) => {
        switch (match) {
          case "Q":
            return Math.ceil((this.$M + 1) / 3);
          case "Do":
            return locale.ordinal(this.$D);
          case "gggg":
            return this.weekYear();
          case "GGGG":
            return this.isoWeekYear();
          case "wo":
            return locale.ordinal(this.week(), "W"); // W for week
          case "w":
          case "ww":
            return utils.s(this.week(), match === "w" ? 1 : 2, "0");
          case "W":
          case "WW":
            return utils.s(this.isoWeek(), match === "W" ? 1 : 2, "0");
          case "k":
          case "kk":
            return utils.s(
              String(this.$H === 0 ? 24 : this.$H),
              match === "k" ? 1 : 2,
              "0"
            );
          case "X":
            return Math.floor(this.$d.getTime() / 1000);
          case "x":
            return this.$d.getTime();
          case "z":
            return `[${this.offsetName()}]`;
          case "zzz":
            return `[${this.offsetName("long")}]`;
          default:
            return match;
        }
      }
    );
    return oldFormat.bind(this)(result);
  };
};