@dhis2/gis-api/src/utils/geometry.js

Maps API for DHIS2 based on Leaflet

import L from 'leaflet'

// Converts from [lat,lng] to [lng,lat]
export const toLatLng = lnglat => [...lnglat].reverse()

// Converts from [lng,lat] to [lat,lng]
export const toLngLat = latlng => {
    if (Array.isArray(latlng)) {
        return [...latlng].reverse()
    } else if (latlng instanceof L.LatLng) {
        return [latlng.lng, latlng.lat]
    }
}

// Converts from [[lng,lat],[lng,lat]] to [[lat,lng],[lat,lng]]
export const toLatLngBounds = bounds => bounds.map(toLatLng)

// Converts from [[lat,lng],[lat,lng]] to [[lng,lat],[lng,lat]]
export const toLngLatBounds = bounds => {
    if (Array.isArray(bounds)) {
        return bounds.map(toLngLat)
    } else if (bounds instanceof L.LatLngBounds) {
        return [
            toLngLat(bounds.getSouthWest()),
            toLngLat(bounds.getNorthEast()),
        ]
    }
}

export const getBoundsFromLayers = layers => {
    const bounds = new L.LatLngBounds()

    layers.forEach(layer => {
        if (!layer.getBounds) {
            return
        }

        const layerBounds = layer.getBounds()

        if (layerBounds && layerBounds.extend) {
            bounds.extend(layerBounds) // lat,lng format
        } else if (Array.isArray(layerBounds)) {
            bounds.extend(toLatLngBounds(layerBounds)) // lng,lat format
        }
    })

    if (bounds.isValid()) {
        return bounds
    }
}

// Convert from GeoJSON coordinates to arrays of [lng,lat]
export const coordsToLatLngs = (coords, levelsDeep) => {
    const latlngs = []

    for (let i = 0, len = coords.length; i < len; i++) {
        latlngs.push(
            levelsDeep
                ? coordsToLatLngs(coords[i], levelsDeep - 1)
                : [coords[i][1], coords[i][0]]
        )
    }

    return latlngs
}