title: How to toggle echarts theme color
body: <p>I am using echarts library in angular 8 application.</p>
  <p>Here is my theme object.</p>
  <pre><code>let customTheme = {
        version: 1,
        themeName: &quot;customed&quot;,
        theme: {
          seriesCnt: 3,
          backgroundColor: &quot;rgba(255,255,255,0)&quot;,
          title: {
            textStyle: {
              fontWeight: &quot;lighter&quot;,
              color: &quot;#008acd&quot;
            }
          },
          color: [
            &quot;#3da4e0&quot;,
            &quot;#779ff1&quot;,
            &quot;#b493f0&quot;,
            &quot;#eb84db&quot;,
            &quot;#ff76b4&quot;,
            &quot;#ff7783&quot;,
          ],
          borderColor: &quot;#ccc&quot;,
          dataZoom: {
            dataBackgroundColor: &quot;#efefff79&quot;,
            dataColor: &quot;rgba(47,69,84,0.3)&quot;,
            fillerColor: &quot;#edf2f979&quot;,
            handleColor: &quot;#008acd79&quot;,
            handleWidth: &quot;100&quot;
          },
          categoryAxis: {
            axisLabel: {
              color: &quot;#ccc&quot;
            },
            axisLine: {
              lineStyle: {
                color: &quot;#008acd&quot;
              }
            },
            splitLine: {
              lineStyle: {
                color: [&quot;#eee&quot;]
              }
            }
          },
          valueAxis: {
            axisLabel: {
              color: &quot;#333&quot;
            }
          }
        }
      };
  </code></pre>
  <p>this.myChart = echarts.init(this.el.nativeElement, customTheme.theme);</p>
  <p>I tried using observable , it doeesnt. update the theme.</p>