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API ReferenceHelper Functions

🛠️ Helper Functions

The GoCharting SDK provides utility functions to help with common tasks like calculating date ranges for datafeed implementations.

📋 Available Helpers

getDateRangeForDuration()

Calculates start and end dates based on a duration string. This is useful for implementing datafeed methods that need to fetch historical data for specific time periods.

Signature:

function getDateRangeForDuration(duration: DurationString): DateRangeResult
 
type DurationString = "1D" | "5D" | "15D" | "1M" | "3M" | "6M" | "1Y" | "5Y" | "All"
 
type DateRangeResult = {
	start_date: number;  // Start timestamp in milliseconds
	end_date: number;    // End timestamp in milliseconds (current time)
	interval: string;    // Recommended interval for this duration
}

Parameters:

  • duration (DurationString): Duration string representing the time period

Returns: Object with:

  • start_date - Start timestamp in milliseconds
  • end_date - End timestamp in milliseconds (current time)
  • interval - Recommended interval for this duration (e.g., “1m”, “15m”, “1h”, “1D”)

Supported Durations:

DurationDescriptionRecommended Interval
"1D"1 day"1m" (1 minute)
"5D"5 days"5m" (5 minutes)
"15D"15 days"15m" (15 minutes)
"1M"1 month"1h" (1 hour)
"3M"3 months"1h" (1 hour)
"6M"6 months"1D" (1 day)
"1Y"1 year"1D" (1 day)
"5Y"5 years"1W" (1 week)
"All"All available data"1M" (1 month)

💡 Usage Examples

Example 1: Basic Usage

import { getDateRangeForDuration } from "@gocharting/chart-sdk";
 
// Get date range for 1 day
const { start_date, end_date, interval } = getDateRangeForDuration("1D");
 
console.log("Start:", new Date(start_date));  // 1 day ago
console.log("End:", new Date(end_date));      // Now
console.log("Interval:", interval);            // "1m"

Example 2: Datafeed Implementation

import { getDateRangeForDuration } from "@gocharting/chart-sdk";
 
const myDatafeed = {
	async getBars(symbolInfo, resolution, periodParams) {
		const { from, to } = periodParams;
 
		// Fetch data from your API
		const response = await fetch(
			`/api/bars?symbol=${symbolInfo.symbol}&from=${from.getTime()}&to=${to.getTime()}`
		);
		const data = await response.json();
 
		return {
			bars: data.map(bar => ({
				time: bar.timestamp,
				open: bar.open,
				high: bar.high,
				low: bar.low,
				close: bar.close,
				volume: bar.volume,
			})),
		};
	},
 
	resolveSymbol(symbolName, onResolve, onError) {
		// Use helper to get initial data range
		const { start_date, end_date, interval } = getDateRangeForDuration("1M");
 
		onResolve({
			symbol: symbolName,
			name: symbolName,
			type: "stock",
			session: "24x7",
			timezone: "Etc/UTC",
			minmov: 1,
			pricescale: 100,
			has_intraday: true,
			supported_resolutions: ["1m", "5m", "15m", "1h", "1D"],
			// Use calculated values
			data_status: "streaming",
		});
	},
};

Example 3: Custom Duration Selector

import { createChart, getDateRangeForDuration } from "@gocharting/chart-sdk";
 
const durations = ["1D", "5D", "15D", "1M", "3M", "6M", "1Y", "5Y"];
 
const chart = createChart("#chart", {
	symbol: "AAPL",
	interval: "1D",
	datafeed: myDatafeed,
	licenseKey: "YOUR_LICENSE_KEY",
	onReady: (chartInstance) => {
		// Add duration selector buttons
		durations.forEach(duration => {
			document.getElementById(`btn-${duration}`).addEventListener("click", () => {
				const { start_date, end_date, interval } = getDateRangeForDuration(duration);
 
				console.log(`Loading ${duration} of data`);
				console.log(`From: ${new Date(start_date)}`);
				console.log(`To: ${new Date(end_date)}`);
				console.log(`Recommended interval: ${interval}`);
 
				// Update chart interval if needed
				chartInstance.setInterval(interval);
 
				// Trigger data reload (implementation depends on your datafeed)
				// Your datafeed's getBars will be called with the new time range
			});
		});
	},
});

Example 4: Pre-loading Data

import { getDateRangeForDuration } from "@gocharting/chart-sdk";
 
async function preloadChartData(symbol, duration) {
	const { start_date, end_date, interval } = getDateRangeForDuration(duration);
 
	// Pre-fetch data before creating chart
	const response = await fetch(
		`/api/bars?symbol=${symbol}&interval=${interval}&from=${start_date}&to=${end_date}`
	);
	const data = await response.json();
 
	console.log(`Pre-loaded ${data.length} bars for ${duration}`);
	return data;
}
 
// Usage
const cachedData = await preloadChartData("AAPL", "1M");
 
const chart = createChart("#chart", {
	symbol: "AAPL",
	interval: "1h",
	datafeed: {
		async getBars(symbolInfo, resolution, periodParams) {
			// Use cached data if available
			if (cachedData) {
				return { bars: cachedData };
			}
			// Otherwise fetch from API
			// ...
		},
		resolveSymbol(symbolName, onResolve, onError) {
			// ...
		},
	},
	licenseKey: "YOUR_LICENSE_KEY",
});

Example 5: Dynamic Interval Selection

import { getDateRangeForDuration } from "@gocharting/chart-sdk";
 
function getOptimalInterval(duration) {
	const { interval } = getDateRangeForDuration(duration);
	return interval;
}
 
// Create chart with optimal interval based on duration
const selectedDuration = "1M";
const optimalInterval = getOptimalInterval(selectedDuration);
 
const chart = createChart("#chart", {
	symbol: "AAPL",
	interval: optimalInterval, // "1h" for 1 month
	datafeed: myDatafeed,
	licenseKey: "YOUR_LICENSE_KEY",
});

📋 Helper Reference

getDateRangeForDuration()

AspectDetails
PurposeCalculate start/end dates and recommended interval for a duration
InputDuration string (“1D”, “5D”, “15D”, “1M”, “3M”, “6M”, “1Y”, “5Y”, “All”)
OutputObject with start_date, end_date (ms), and interval
Use CaseDatafeed implementations, date range calculations
Importimport { getDateRangeForDuration } from "@gocharting/chart-sdk"
Note

Important Notes:

  1. Timestamps: All timestamps are in milliseconds (JavaScript standard)
  2. Current Time: The end_date is always the current time when the function is called
  3. Recommended Intervals: The returned interval is a suggestion based on the duration. You can use a different interval if needed.
  4. Timezone: All calculations are based on the user’s local timezone
  5. “All” Duration: The “All” duration returns a very large time range (typically 10+ years)

🔗 Related Documentation

For complete working examples, see the Examples section.

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