Indy Charts

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API client ​

createApiClient() returns a small, typed wrapper around fetch that knows how to talk to the stock-charts REST API. It does not own any chart state — it only fetches and normalizes data.

Create a client ​

typescript
import { createApiClient } from "@facioquo/indy-charts";

const client = createApiClient({
  baseUrl: "https://api.example.com",
  onError: (context, error) => console.error(`[indy-charts] ${context}`, error)
});

The baseUrl may include or omit a trailing slash — the client normalizes it.

ApiClientConfig ​

typescript
interface ApiClientConfig {
  /** Root URL of the API. Trailing slash is optional. */
  baseUrl: string;

  /** Optional endpoint path overrides (when the API mounts routes elsewhere). */
  endpoints?: {
    quotes?: string;       // default: "quotes"
    indicators?: string;   // default: "indicators"
  };

  /**
   * Called whenever a fetch operation throws or receives a non-2xx response.
   * The error is re-thrown after the callback returns — callers must still
   * handle the rejected promise.
   */
  onError?: (context: string, error: unknown) => void;
}

Methods ​

The returned ApiClient exposes three methods. All return promises that reject (after onError) on network or HTTP failures.

getQuotes(): Promise<Quote[]> ​

Fetches OHLCV history from GET {baseUrl}/quotes and normalizes the response into Quote objects (timestamps parsed to Date).

typescript
const quotes = await client.getQuotes();

getListings(): Promise<IndicatorListing[]> ​

Fetches the indicator catalog from GET {baseUrl}/indicators. Each listing describes one indicator (uiid, parameters, default colors, oscillator/overlay type).

typescript
const listings = await client.getListings();
const ema = listings.find(l => l.uiid === "EMA");

getSelectionData(selection, listing): Promise<unknown[]> ​

Fetches computed indicator rows. The endpoint path comes from listing.endpoint; query-string parameters are derived from selection.params.

typescript
import { createDefaultSelection, loadStaticIndicatorData } from "@facioquo/indy-charts";

const selection = createDefaultSelection(emaListing, { lookbackPeriods: 20 });
const rawRows = await client.getSelectionData(selection, emaListing);
const rows = loadStaticIndicatorData(rawRows);

Wrap the result in loadStaticIndicatorData() to get a typed IndicatorDataRow[].

Data shape ​

After normalization, quote data conforms to:

typescript
interface Quote {
  timestamp: Date;
  open: number;
  high: number;
  low: number;
  close: number;
  volume: number;
}

Invalid timestamps (missing, non-string/Date, or NaN after parsing) cause getQuotes() to throw an Error with the row index.

Error handling ​

typescript
const client = createApiClient({
  baseUrl: "https://api.example.com",
  onError: (context, error) => {
    // Surface the error to your logging/telemetry layer.
    console.error(`[indy-charts] ${context}`, error);
  }
});

try {
  const quotes = await client.getQuotes();
} catch (err) {
  // onError already fired — handle the failure (fallback, retry, UI state).
}

onError is observational, not recovery. The promise still rejects with the original error so callers can decide how to react.

Custom endpoint paths ​

If your deployment mounts the API under a non-default route:

typescript
const client = createApiClient({
  baseUrl: "https://api.example.com",
  endpoints: {
    quotes: "v2/market/quotes",
    indicators: "v2/market/indicators"
  }
});

getSelectionData always uses listing.endpoint, so per-indicator routes come from the listings response — no client-side override needed.

Next steps ​