signalk-tides/dist/sources/stormglass.js

Tidal predictions for the vessel's position from various online sources.

import moment from 'moment';
export default function (app) {
    return {
        id: 'stormglass',
        title: 'StormGlass.io',
        properties: {
            stormglassApiKey: {
                type: 'string',
                title: 'StormGlass.io API key'
            }
        },
        start({ stormglassApiKey } = {}) {
            app.debug("Using StormGlass.io API");
            return async ({ position, date = moment().subtract(1, "days").toISOString() }) => {
                const endPoint = new URL("https://api.stormglass.io/v2/tide/extremes/point");
                endPoint.search = new URLSearchParams({
                    start: moment(date).format("YYYY-MM-DD"),
                    end: moment(date).add(7, "days").format("YYYY-MM-DD"),
                    // datum: "CD",
                    lat: position.latitude.toString(),
                    lng: position.longitude.toString()
                }).toString();
                app.debug("Fetching StormGlass.io: " + endPoint.toString());
                const res = await fetch(endPoint, {
                    headers: { Authorization: stormglassApiKey ?? '' },
                });
                if (!res.ok)
                    throw new Error('Failed to fetch StormGlass.io: ' + res.statusText);
                const data = await res.json();
                app.debug(JSON.stringify(data, null, 2));
                return {
                    station: {
                        name: `${data.meta.station.name} (${data.meta.station.source})`,
                        position: {
                            latitude: data.meta.station.lat,
                            longitude: data.meta.station.lng,
                        },
                    },
                    extremes: data.data.map(({ type, time, height }) => {
                        return {
                            type: type === "high" ? "High" : "Low",
                            value: height,
                            time: new Date(time).toISOString(),
                        };
                    }),
                };
            };
        }
    };
}