fix(geojson): geometry is null

.eslintignore

@@ -10,4 +10,5 @@ demos/index.html
 demos/*
 rollup/*
 webpack/*
-src/core/three.js
+src/core/three.js
+testdemo/*

.gitignore

@@ -74,4 +74,5 @@ demos/data
 demos/image
 .vscode
 demos/hexagon.html
-demos/model
+demos/model
+testdemo

demos/04_choropleths_polygon.html

@@ -61,7 +61,7 @@ const scene = new L7.Scene({
 window.scene = scene;
 scene.on('loaded', () => {
   var colors = ["#FFF5B8","#FFDC7D","#FFAB5C","#F27049","#D42F31","#730D1C"];
-  $.getJSON('https://gw.alipayobjects.com/os/basement_prod/7224a078-e3a3-4cc3-8749-7026af9e5c7f.json', city => {
+  $.getJSON('https://gw.alipayobjects.com/os/basement_prod/77497aa8-8dd0-4a0c-bf3b-3bb55c5d453c.json', city => {
    
     const citylayer = scene.PolygonLayer()
     .source(city)

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@antv/l7",
-  "version": "1.1.9",
+  "version": "1.1.10",
   "description": "Large-scale WebGL-powered Geospatial Data Visualization",
   "main": "build/l7.js",
   "browser": "build/l7.js",

src/source/parser/geojson.js

@@ -3,6 +3,7 @@ import { getCoords } from '@turf/invariant';
 
 export default function geoJSON(data) {
   const resultData = [];
+  // 数据为空时处理
   turfMeta.flattenEach(data, (currentFeature, featureIndex) => { // 多个polygon 拆成一个
     const coord = getCoords(currentFeature);
     const dataItem = {