1、首先，确保你已经引入了Turf.js库。你可以通过在HTML文件中添加以下代码来引入

<script src="https://cdn.jsdelivr.net/npm/@turf/turf@6.5.0/turf.min.js"></script>

2、使用turf.buffer实现几何对象按照设定距离扩充

    let originalCoordinates = [
            [ -0.13236090490727292, 51.50456971900687],
            [-0.11407896826176511,  51.506760740677095,],
            [ -0.10206267187504636, 51.4987977430076,],
            [-0.10901495764164792, 51.486449673535816],
            [-0.12034460852055417,  51.49778222716637],
            [ -0.13236090490727292, 51.50456971900687]
          ];
        // 将坐标数组转换为Turf.js的多边形对象
        var originalPolygon = turf.polygon([originalCoordinates]);
        // 定义外扩距离
        var expandDistance = 0.1;
        // 使用Turf.js的buffer方法来扩大多边形的边界
        expandedPolygon = turf.buffer(originalPolygon, expandDistance, { units: 'kilometers' });
        console.log(expandedPolygon.geometry);

效果图如下