pleno-vue/src/services/dateOnly.js

const DATE_ONLY_PATTERN = /^(\d{4})-(\d{2})-(\d{2})$/;
const DATE_ONLY_PREFIX_PATTERN = /^(\d{4}-\d{2}-\d{2})/;

const padDatePart = (value) => String(value).padStart(2, "0");

export const isValidDate = (value) => value instanceof Date && !Number.isNaN(value.getTime());

export const formatLocalDateOnly = (value = new Date()) => {
  if (typeof value === "string") {
    const directMatch = value.trim().match(DATE_ONLY_PREFIX_PATTERN);
    if (directMatch) {
      return directMatch[1];
    }
  }

  const date = value instanceof Date ? value : new Date(value);
  if (!isValidDate(date)) {
    return "";
  }

  return [
    date.getFullYear(),
    padDatePart(date.getMonth() + 1),
    padDatePart(date.getDate()),
  ].join("-");
};

export const parseLocalDateOnly = (value) => {
  if (value instanceof Date) {
    return isValidDate(value)
      ? new Date(value.getFullYear(), value.getMonth(), value.getDate())
      : new Date(Number.NaN);
  }

  const stringValue = String(value ?? "").trim();
  const match = DATE_ONLY_PATTERN.exec(stringValue);
  if (match) {
    const year = Number(match[1]);
    const month = Number(match[2]);
    const day = Number(match[3]);
    const parsed = new Date(year, month - 1, day);

    if (
      parsed.getFullYear() === year
      && parsed.getMonth() === month - 1
      && parsed.getDate() === day
    ) {
      return parsed;
    }

    return new Date(Number.NaN);
  }

  const parsed = new Date(stringValue);
  return isValidDate(parsed)
    ? new Date(parsed.getFullYear(), parsed.getMonth(), parsed.getDate())
    : parsed;
};

export const todayLocalDateOnly = () => formatLocalDateOnly(new Date());

export const yesterdayLocalDateOnly = () => {
  const yesterday = new Date();
  yesterday.setDate(yesterday.getDate() - 1);
  return formatLocalDateOnly(yesterday);
};

export const startOfLocalDate = (value) => {
  const date = parseLocalDateOnly(value);
  if (!isValidDate(date)) {
    return date;
  }
  date.setHours(0, 0, 0, 0);
  return date;
};

export const endOfLocalDate = (value) => {
  const date = parseLocalDateOnly(value);
  if (!isValidDate(date)) {
    return date;
  }
  date.setHours(23, 59, 59, 999);
  return date;
};