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Version: 7.2.0

propReduce

描述​

¥Description

将任何 GeoJSON 对象中的属性简化为单个值，类似于 Array.reduce 的工作方式。但是，在本例中，我们延迟运行归约，因此不需要包含所有属性的数组。

¥Reduce properties in any GeoJSON object into a single value, similar to how Array.reduce works. However, in this case we lazily run the reduction, so an array of all properties is unnecessary.

参数​

¥Parameters

名称类型描述
geojsonFeatureCollection | 特性 | 几何图形任意 GeoJSON 对象
callbackpropReduceCallback一个方法，该方法接受 (previousValue, currentProperties, featureIndex)
initialValue?Reducer用作回调函数首次调用的第一个参数的值。

返回​

¥Returns

Reducer 简化后的值。

¥Reducer The value that results from the reduction.

示例​

¥Examples

var features = turf.featureCollection([
  turf.point([26, 37], { foo: "bar" }),
  turf.point([36, 53], { hello: "world" }),
]);

turf.propReduce(
  features,
  function (previousValue, currentProperties, featureIndex) {
    //=previousValue
    //=currentProperties
    //=featureIndex
    return currentProperties;
  },
);

安装​

¥Installation

$ npm install @turf/meta

import { propReduce } from "@turf/meta";
const result = propReduce(...);
$ npm install @turf/turf

import * as turf from "@turf/turf";
const result = turf.propReduce(...);