@tamtamchik/exchanger/dist/index.mjs

Simple and free npm library to get realtime currency exchange rates.

// src/errors.ts
var ApplicationError = class extends Error {
  constructor(errorType, errorMessage) {
    super(errorMessage);
    this.name = errorType;
    this.captureStackTrace();
  }
  captureStackTrace() {
    if (Error.captureStackTrace) {
      Error.captureStackTrace(this, this.constructor);
    }
  }
};
var NetworkError = class extends ApplicationError {
  constructor(message) {
    super("NetworkError", message);
  }
};
var ServerError = class extends ApplicationError {
  constructor(message) {
    super("ServerError", message);
  }
};
var DataError = class extends ApplicationError {
  constructor(message) {
    super("DataError", message);
  }
};

// src/index.ts
var YAHOO_FINANCE_BASE_URL = "https://query1.finance.yahoo.com/v8/finance/chart/";
var YAHOO_FINANCE_QUERY_PARAMS = "=X?region=US&lang=en-US&includePrePost=false&interval=2m&useYfid=true&range=1d&corsDomain=finance.yahoo.com&.tsrc=finance";
var rateCache = /* @__PURE__ */ new Map();
function buildRateUrl(fromCurrency, toCurrency) {
  return `${YAHOO_FINANCE_BASE_URL}${fromCurrency.toUpperCase()}${toCurrency.toUpperCase()}${YAHOO_FINANCE_QUERY_PARAMS}`;
}
function isCacheValid(cachedRate, cacheDurationMs) {
  return Date.now() - cachedRate.timestamp < cacheDurationMs;
}
function getCachedRate(fromCurrency, toCurrency, cacheDurationMs) {
  if (!cacheDurationMs) return null;
  const cacheKey = `${fromCurrency}-${toCurrency}`;
  const cachedRate = rateCache.get(cacheKey);
  return cachedRate && isCacheValid(cachedRate, cacheDurationMs) ? cachedRate.value : null;
}
async function fetchExchangeRateResponse(rateUrl) {
  const response = await fetch(rateUrl);
  if (!response.ok) {
    throw new ServerError(`HTTP ${response.status}: ${response.statusText}`);
  }
  return response;
}
function extractRateFromResponse(response) {
  const rate = response.chart?.result[0]?.meta?.regularMarketPrice;
  if (typeof rate !== "number" || isNaN(rate)) {
    throw new DataError('Invalid or missing "regularMarketPrice" in response.');
  }
  return rate;
}
async function fetchExchangeRate(rateUrl) {
  try {
    const response = await fetchExchangeRateResponse(rateUrl);
    const responseData = await response.json();
    return extractRateFromResponse(responseData);
  } catch (error) {
    if (error instanceof ServerError || error instanceof DataError) {
      throw error;
    }
    throw new NetworkError(
      `Failed to fetch exchange rate: ${error instanceof Error ? error.message : String(error)}`
    );
  }
}
async function getExchangeRate(fromCurrency, toCurrency, options = {}) {
  const { cacheDurationMs } = options;
  const cachedRate = getCachedRate(fromCurrency, toCurrency, cacheDurationMs);
  if (cachedRate !== null) {
    return cachedRate;
  }
  const rateUrl = buildRateUrl(fromCurrency, toCurrency);
  const rate = await fetchExchangeRate(rateUrl);
  if (cacheDurationMs) {
    const cacheKey = `${fromCurrency}-${toCurrency}`;
    rateCache.set(cacheKey, { value: rate, timestamp: Date.now() });
  }
  return rate;
}
export {
  DataError,
  NetworkError,
  ServerError,
  getExchangeRate
};