signalk-tides/dist/sources/worldtides.js

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

import moment from 'moment';
export default function (app) {
    return {
        id: 'WorldTides.info',
        title: 'worldtides.info',
        properties: {
            worldtidesApiKey: {
                type: 'string',
                title: 'worldtides.info API key'
            }
        },
        start({ worldtidesApiKey = '' } = {}) {
            app.debug("Using WorldTides API");
            return async (params) => {
                const { position, date = moment().subtract(1, "days") } = params;
                const endPoint = new URL("https://www.worldtides.info/api/v3");
                endPoint.search = new URLSearchParams({
                    date: moment(date).format("YYYY-MM-DD"),
                    datum: "CD",
                    days: "7",
                    extremes: "true",
                    key: worldtidesApiKey,
                    lat: position.latitude.toString(),
                    lon: position.longitude.toString(),
                }).toString();
                app.debug("Fetching worldtides: " + endPoint.toString());
                const res = await fetch(endPoint);
                if (!res.ok)
                    throw new Error('Failed to fetch worldtides: ' + res.statusText);
                const data = await res.json();
                app.debug(JSON.stringify(data, null, 2));
                if (data.status != 200)
                    throw new Error("worldtides data: " + data.error ? data.error : "none");
                return {
                    station: {
                        name: `${data.station} (${data.atlas})`,
                        position: {
                            latitude: data.responseLat,
                            longitude: data.responseLon,
                        },
                    },
                    extremes: data.extremes.map(({ type, dt, height }) => {
                        return {
                            type,
                            value: height,
                            time: new Date(dt * 1000).toISOString(),
                        };
                    }),
                };
            };
        }
    };
}