austrian-cpi/src/cpiUtils.js

Query and merge Austrian CPI time series data for economic modeling

import { austrianCPI } from "../austrianCPI.js";

/**
 * Internal helper to extract sorted CPI data
 * @param {string} seriesKey
 * @param {'monthly'|'yearly'} frequency
 * @param {string|null} start
 * @param {string|null} end
 * @returns {Array<{ date: string, value: number }>}
 */
function extractSeriesValues(
  seriesKey,
  frequency = "monthly",
  start = null,
  end = null,
) {
  return austrianCPI
    .map((row) => {
      const parsed = parsePeriod(row);
      if (!parsed || parsed.type !== frequency) return null;

      const dateKey = parsed.key;
      if (start && dateKey < start) return null;
      if (end && dateKey > end) return null;

      let val = row[seriesKey];
      if (
        val === "None" ||
        val === undefined ||
        val === null ||
        typeof val === "object"
      )
        return null;
      val = typeof val === "string" ? parseFloat(val.replace(",", ".")) : val;

      return { date: dateKey, value: val };
    })
    .filter(Boolean)
    .sort((a, b) => a.date.localeCompare(b.date));
}

function padMonth(month) {
  return month.length === 1 ? "0" + month : month;
}

// helper
function parsePeriod(entry) {
  let period = entry && entry.period ? entry.period : "";
  if (!period) return null;

  period = period
    .replace(/[\u00A0\u202F\u200E\u200F]/g, " ")
    .replace(/\s+/g, " ")
    .trim();

  if (period.startsWith("Ø")) {
    const yearStr = period.slice(2).trim();
    const fullYear =
      yearStr.length === 2
        ? parseInt(yearStr, 10) > 50
          ? "19" + yearStr
          : "20" + yearStr
        : yearStr;
    return {
      type: "yearly",
      year: parseInt(fullYear, 10),
      key: fullYear,
    };
  }

  const match = period.match(/^([A-Za-zÄÖÜäöüß]{3,4})\.\s*(\d{2})$/);
  if (!match) return null;

  const monthStr = match[1];
  const yearStr = match[2];
  const monthMap = {
    // German
    Jän: "01",
    Feb: "02",
    Mär: "03",
    Apr: "04",
    Mai: "05",
    Jun: "06",
    Jul: "07",
    Aug: "08",
    Sep: "09",
    Okt: "10",
    Nov: "11",
    Dez: "12",

    // EN (3- or 4-letter forms)
    Jan: "01",
    Mar: "03",
    May: "05",
    Sept: "09",
    Oct: "10",
    Dec: "12",
  };

  const month = monthMap[monthStr];
  if (!month) return null;

  const fullYear = parseInt(yearStr, 10) > 50 ? "19" + yearStr : "20" + yearStr;
  return {
    type: "monthly",
    year: parseInt(fullYear, 10),
    month: parseInt(month, 10),
    key: fullYear + "-" + month,
  };
}

/**
 * Normalize YYYY-MM dates, e.g. 2023-1 -> 2023-01
 */
function normalizeDate(dateStr) {
  if (!dateStr || typeof dateStr !== "string") return "";
  const parts = dateStr.trim().split("-");
  if (parts.length === 2) {
    const year = parts[0];
    const month = padMonth(parts[1]);
    return `${year}-${month}`;
  }
  return dateStr.trim();
}

export { extractSeriesValues, normalizeDate, parsePeriod };