Echarts學習求教

有沒有人用過百度的Echarts？剛開始接觸，下面這段代碼怎么理解啊，新手求指教：

myChart.showLoading();
$.get('data/asset/data/les-miserables.gexf', function (xml) {
myChart.hideLoading();

var graph = echarts.dataTool.gexf.parse(xml);
var categories = [];
for (var i = 0; i < 9; i++) {
categories[i] = {
name: '類目' + i
};
}
graph.nodes.forEach(function (node) {
node.itemStyle = null;
node.value = node.symbolSize;
node.label = {
normal: {
show: node.symbolSize > 30
}
};
node.category = node.attributes.modularity_class;
});