Source: createLayer.js

import sourceVector from 'ol/source/Vector';
import layerVector from 'ol/layer/Vector';

/**
 * 创建图层
 * @param {object} extra 自定义参数
 * @return layer 实例
 */
function createLayer(extra) {
	let obj = Object.assign({ source: new sourceVector(), extra });
    let layer = new layerVector(obj);
    
    return layer;
}

export default createLayer;