Проверка адреса с помощью карты полигонов React Native и Leaflet

Решение:

import {
  View,
  Text,
  StyleSheet,
  TouchableOpacity,
  Dimensions,
  Button,
  TextInput,
  Alert,
} from "react-native";
import React, { useEffect, useState } from "react";
import { Entypo } from "@expo/vector-icons";
import allVariables from "../utils/allVariables";

const screenWidth = Dimensions.get("window").width;

function rayCasting(point, polygon) {
  const n = polygon.length;
  let isIn = false;
  const x = point[0];
  const y = point[1];
  let x1, x2, y1, y2;

  x1 = polygon[n - 1][0];
  y1 = polygon[n - 1][1];

  for (let i = 0; i < n; ++i) {
    x2 = polygon[i][0];
    y2 = polygon[i][1];

    if (y < y1 !== y < y2 && x < ((x2 - x1) * (y - y1)) / (y2 - y1) + x1) {
      isIn = !isIn;
    }
    x1 = x2;
    y1 = y2;
  }

  return isIn;
}

const CurrentLocationPanel = ({ closeCL }) => {
  const [data, setData] = useState(null);
  const [address, setAddress] = useState("");
  const [point, setPoint] = useState(null);

  useEffect(() => {
    const fetchData = async () => {
      try {
        const response = await fetch(
          `${allVariables.strapiBaseURL}/api/mapvalidations/1`,
          {
            headers: {
              Authorization: `Bearer ${allVariables.strapiApiUpdateMapBearer}`,
            },
          }
        );
        if (!response.ok) {
          throw new Error(`HTTP error! status: ${response.status}`);
        }
        const jsonData = await response.json();
        setData(jsonData);
      } catch (error) {
        console.error("Fetch error:", error);
      }
    };
    fetchData();
  }, []);

  const polygon = data?.data?.attributes?.polygon?.[0]?.latlngs?.map(
    (latlng) => [latlng.lng, latlng.lat]
  );

  const handleValidate = async () => {
    if (!address) {
      Alert.alert("Please enter an address.");
      return;
    }

    try {
      const response = await fetch(
        `https://nominatim.openstreetmap.org/search?q=${encodeURIComponent(
          address
        )}&format=json&limit=1`
      );
      if (!response.ok) {
        throw new Error(`HTTP error! status: ${response.status}`);
      }
      const jsonData = await response.json();
      if (!jsonData.length) {
        Alert.alert("Address not found.");
        return;
      }
      const { lat, lon } = jsonData[0];
      const point = [parseFloat(lon), parseFloat(lat)];
      const isInsidePolygon = rayCasting(point, polygon);
      Alert.alert(
        "Validation Result",
        isInsidePolygon
          ? "The entered address is inside the polygon."
          : "The entered address is outside the polygon.",
        [{ text: "OK" }]
      );
    } catch (error) {
      console.error("Fetch error:", error);
      Alert.alert("Something went wrong. Please try again later.");
    }
  };

  return (
    <>
      <TouchableOpacity
        style = {styles.mainViewNoBG}
        onPress = {closeCL}
        activeOpacity = {0}
      ></TouchableOpacity>
      <View style = {styles.blockView}>
        <TouchableOpacity
          style = {styles.closeBtn}
          activeOpacity = {0.5}
          onPress = {closeCL}
        >
          <Entypo
            name = "circle-with-cross"
            size = {24}
            color = {allVariables.headerColor}
          />
        </TouchableOpacity>
        <Text>CurrentLocationPanel</Text>
        <TextInput
          style = {styles.input}
          placeholder = "Enter Address"
          value = {address}
          onChangeText = {setAddress}
        />
        <Button title = "Validate" onPress = {handleValidate} />
        <Button
          title = "Log Data"
          onPress = {() => console.info(JSON.stringify(data))}
        />
        <Button title = "Log Polygon Data" onPress = {() => console.info(polygon)} />
      </View>
    </>
  );
};
const styles = StyleSheet.create({
  mainViewNoBG: {
    width: "100%",
    height: "100%",
    backgroundColor: "transparent",
    position: "absolute",
  },
  blockView: {
    backgroundColor: "white",
    borderRadius: 10,
    top: screenWidth >= 768 ? 75 : 60,
    alignSelf: "center",
    alignItems: "center",
    justifyContent: "center",
    position: "absolute",
    width: screenWidth >= 768 ? "50%" : "75%",
    height: "auto",
    padding: 10,
    borderWidth: 1,
    borderColor: "black",
  },
  closeBtn: {
    position: "absolute",
    zIndex: 9999,
    right: 10,
    top: 10, // use top 20 if device is iOS, otherwise use top 10
  },
});

export default CurrentLocationPanel;

Я использовал функцию RayCasting, а также преобразовал предоставленный адрес в широту и долготу, чтобы позже проверить, находится ли он внутри полигона.

В результате, независимо от того, сколько точек у многоугольника, он всегда будет давать правильный ответ.