echarts图例点击反选

默认展示单项数据

image.png
反选：
https://www.cnblogs.com/xiaxuening/p/10971983.html

this.echart.on('legendselectchanged', function(obj) {
                const {selected, name} = obj;
                if (first && selected) {
                    Object.keys(selected).forEach(key => {
                        selected[key] = key === name ? true : false;
                    });
                    first = false;
                } else {
                    let open = selected[name];
                    selected[name] = open;
                }
                option.legend.selected = selected;
                this.setOption(option);
            });

first删掉，注意this指向