node-red-contrib-tak-registration
Version:
A Node-RED node to register to TAK and to help wrap files as datapackages to send to TAK
72 lines (71 loc) • 2.29 kB
JavaScript
import clone from "@turf/clone";
import { isObject } from "@turf/helpers";
import { getType } from "@turf/invariant";
import { flattenEach } from "@turf/meta";
import lineDissolve from "./turf-line-dissolve.js";
import polygonDissolve from "./turf-polygon-dissolve.js";
/**
* Transform function: attempts to dissolve geojson objects where possible
* [GeoJSON] -> GeoJSON geometry
*
* @private
* @param {FeatureCollection<LineString|MultiLineString|Polygon|MultiPolygon>} geojson Features to dissolved
* @param {Object} [options={}] Optional parameters
* @param {boolean} [options.mutate=false] Prevent input mutation
* @returns {Feature<MultiLineString|MultiPolygon>} Dissolved Features
*/
function dissolve(geojson, options) {
if (options === void 0) { options = {}; }
// Optional parameters
options = options || {};
if (!isObject(options)) {
throw new Error("options is invalid");
}
var mutate = options.mutate;
// Validation
if (getType(geojson) !== "FeatureCollection") {
throw new Error("geojson must be a FeatureCollection");
}
if (!geojson.features.length) {
throw new Error("geojson is empty");
}
// Clone geojson to avoid side effects
// Topojson modifies in place, so we need to deep clone first
if (mutate === false || mutate === undefined) {
geojson = clone(geojson);
}
// Assert homogenity
var type = getHomogenousType(geojson);
if (!type) {
throw new Error("geojson must be homogenous");
}
// Data => Typescript hack
var data = geojson;
switch (type) {
case "LineString":
return lineDissolve(data, options);
case "Polygon":
return polygonDissolve(data, options);
default:
throw new Error(type + " is not supported");
}
}
/**
* Checks if GeoJSON is Homogenous
*
* @private
* @param {GeoJSON} geojson GeoJSON
* @returns {string|null} Homogenous type or null if multiple types
*/
function getHomogenousType(geojson) {
var types = {};
flattenEach(geojson, function (feature) {
types[feature.geometry.type] = true;
});
var keys = Object.keys(types);
if (keys.length === 1) {
return keys[0];
}
return null;
}
export default dissolve;