Question

Enforce expectations about types of FeatureCollection inputs for Turf. Internally this uses geojsonType to judge geometry types.
强制要求Turf库的输入必须是 FeatureCollection 类型，且几何类型符合预期。在内部，其使用geojsonType来判断几何类型。

> npm install @turf/invariant

参数

参数	类型	描述
featureCollection	FeatureCollection	一个将对Features进行判断的FeatureCollection
type	string	预期的GeoJSON类型
name	string	调用函数的名称

示例

var locationA = turf.point([-75.343, 39.984], {name: 'Location A'});
var locationB = turf.point([-75.833, 39.284], {name: 'Location B'});
var locationC = turf.point([-75.534, 39.123], {name: 'Location C'});

var pointCollection = turf.featureCollection([
  locationA,
  locationB,
  locationC
]);

turf.collectionOf(pointCollection, 'Point', 'Location A');