Open-Meteo API Typescript SDK

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This is a TypeScript/Javascript API client designed for retrieving weather information from the Open-Meteo Weather API in Typescript / Javascript.

Unlike conventional JSON APIs, this API client employs FlatBuffers for data transfer. This is a more efficient method, particularly for handling extended time-series data. You can locate the schema definition files on GitHub open-meteo/sdk.

Features:

- Easily access weather data
- Retrieve weather data for multiple locations with a single request
- Automatic retry mechanism for handling errors
- Enhanced bandwidth efficiency and speedy parsing using FlatBuffers and Zero Copy technology
- Type annotations for enhanced code clarity

Install

``bash
npm install openmeteo
`

Usage

Note: The Open-Meteo API documentation generates the required Typescript code automatically.

`ts
import { fetchWeatherApi } from 'openmeteo';

const params = {
latitude: [52.54],
longitude: [13.41],
current: 'temperature_2m,weather_code,wind_speed_10m,wind_direction_10m',
hourly: 'temperature_2m,precipitation',
daily: 'weather_code,temperature_2m_max,temperature_2m_min'
};
const url = 'https://api.open-meteo.com/v1/forecast';
const responses = await fetchWeatherApi(url, params);

// Helper function to form time ranges
const range = (start: number, stop: number, step: number) =>
Array.from({ length: (stop - start) / step }, (_, i) => start + i * step);

// Process first location. Add a for-loop for multiple locations or weather models
const response = responses[0];

// Attributes for timezone and location
const utcOffsetSeconds = response.utcOffsetSeconds();
const timezone = response.timezone();
const timezoneAbbreviation = response.timezoneAbbreviation();
const latitude = response.latitude();
const longitude = response.longitude();

const current = response.current()!;
const hourly = response.hourly()!;
const daily = response.daily()!;

// Note: The order of weather variables in the URL query and the indices below need to match!
const weatherData = {
current: {
time: new Date((Number(current.time()) + utcOffsetSeconds) * 1000),
temperature: current.variables(0)!.value(), // Current is only 1 value, therefore .value()
weatherCode: current.variables(1)!.value(),
windSpeed: current.variables(2)!.value(),
windDirection: current.variables(3)!.value()
},
hourly: {
time: range(Number(hourly.time()), Number(hourly.timeEnd()), hourly.interval()).map(
(t) => new Date((t + utcOffsetSeconds) * 1000)
),
temperature: hourly.variables(0)!.valuesArray()!, // .valuesArray() get an array of floats
precipitation: hourly.variables(1)!.valuesArray()!,
},
daily: {
time: range(Number(daily.time()), Number(daily.timeEnd()), daily.interval()).map(
(t) => new Date((t + utcOffsetSeconds) * 1000)
),
weatherCode: daily.variables(0)!.valuesArray()!,
temperatureMax: daily.variables(1)!.valuesArray()!,
temperatureMin: daily.variables(2)!.valuesArray()!,
}
};

// weatherData now contains a simple structure with arrays for datetime and weather data
for (let i = 0; i < weatherData.daily.time.length; i++) {
console.log(
weatherData.daily.time[i].toISOString(),
weatherData.daily.weatherCode[i],
weatherData.daily.temperatureMax[i],
weatherData.daily.temperatureMin[i]
);
}
`

Parameter

This package only exposes one function to fetch weather data and decode the FlatBuffer messages.

`ts
/**
* Retrieve data from the Open-Meteo weather API
*
* @param {string} url Server and endpoint. E.g. "https://api.open-meteo.com/v1/forecast"
* @param {any} params URL parameter as an object
* @param {number} [retries=3] Number of retries in case of an server error
* @param {number} [backoffFactor=0.2] Exponential backoff factor to increase wait time after each retry
* @param {number} [backoffMax=2] Maximum wait time between retries
* @returns {Promise}
*/
async function fetchWeatherApi(
url: string,
params: any,
retries = 3,
backoffFactor = 0.2,
backoffMax = 2
): Promise {
}
`

Authentication

If the API requires authentication, you can pass the necessary headers using the fetchOptions parameter.

`ts
import { fetchWeatherApi } from 'openmeteo';

const params = {
latitude: [52.54],
longitude: [13.41],
current: 'temperature_2m,weather_code,wind_speed_10m,wind_direction_10m',
hourly: 'temperature_2m,precipitation',
daily: 'weather_code,temperature_2m_max,temperature_2m_min'
};
const url = 'https://api.self-host.example.net/v1/forecast';
const fetchOptions = {
headers: {
'Authorization': 'Bearer YOUR_API_KEY'
}
};
const responses = await fetchWeatherApi(url, params, 3, 0.2, 2, fetchOptions);

// Process the response as shown in the previous example
`

AbortController

You can also use AbortController to cancel the request if needed.

`ts
import { fetchWeatherApi } from 'openmeteo';

const params = {
latitude: [52.54],
longitude: [13.41],
current: 'temperature_2m,weather_code,wind_speed_10m,wind_direction_10m',
hourly: 'temperature_2m,precipitation',
daily: 'weather_code,temperature_2m_max,temperature_2m_min'
};
const url = 'https://api.open-meteo.com/v1/forecast';
const controller = new AbortController();
const fetchOptions = {
signal: controller.signal
};

// Start the request
const fetchPromise = fetchWeatherApi(url, params, 3, 0.2, 2, fetchOptions);

// Abort the request after 5 seconds
setTimeout(() => controller.abort(), 5000);

try {
const responses = await fetchPromise;
// Process the response as shown in the previous example
} catch (error) {
if (error.name === 'AbortError') {
console.log('Request was aborted');
} else {
console.error('Fetch error:', error);
}
}
``

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