contains.js

import {default as polygonContains} from "./polygonContains";
import {default as distance} from "./distance";
import {epsilon, radians} from "./math";

var containsObjectType = {
  Feature: function(object, point) {
    return containsGeometry(object.geometry, point);
  },
  FeatureCollection: function(object, point) {
    var features = object.features, i = -1, n = features.length;
    while (++i < n) if (containsGeometry(features[i].geometry, point)) return true;
    return false;
  }
};

var containsGeometryType = {
  Sphere: function() {
    return true;
  },
  Point: function(object, point) {
    return containsPoint(object.coordinates, point);
  },
  MultiPoint: function(object, point) {
    var coordinates = object.coordinates, i = -1, n = coordinates.length;
    while (++i < n) if (containsPoint(coordinates[i], point)) return true;
    return false;
  },
  LineString: function(object, point) {
    return containsLine(object.coordinates, point);
  },
  MultiLineString: function(object, point) {
    var coordinates = object.coordinates, i = -1, n = coordinates.length;
    while (++i < n) if (containsLine(coordinates[i], point)) return true;
    return false;
  },
  Polygon: function(object, point) {
    return containsPolygon(object.coordinates, point);
  },
  MultiPolygon: function(object, point) {
    var coordinates = object.coordinates, i = -1, n = coordinates.length;
    while (++i < n) if (containsPolygon(coordinates[i], point)) return true;
    return false;
  },
  GeometryCollection: function(object, point) {
    var geometries = object.geometries, i = -1, n = geometries.length;
    while (++i < n) if (containsGeometry(geometries[i], point)) return true;
    return false;
  }
};

function containsGeometry(geometry, point) {
  return geometry && containsGeometryType.hasOwnProperty(geometry.type)
      ? containsGeometryType[geometry.type](geometry, point)
      : false;
}

function containsPoint(coordinates, point) {
  return distance(coordinates, point) === 0;
}

function containsLine(coordinates, point) {
  var ab = distance(coordinates[0], coordinates[1]),
      ao = distance(coordinates[0], point),
      ob = distance(point, coordinates[1]);
  return ao + ob <= ab + epsilon;
}

function containsPolygon(coordinates, point) {
  return !!polygonContains(coordinates.map(ringRadians), pointRadians(point));
}