map is not work

[liuyunqiang]

Error evaluating injectedJavaScript: This is possibly due to an unsupported return type. Try adding true to the end of your injectedJavaScript string. Error Domain=WKErrorDomain Code=4 "A JavaScript exception occurred" UserInfo={WKJavaScriptExceptionLineNumber=3, WKJavaScriptExceptionMessage=ReferenceError: Can't find variable: echarts, WKJavaScriptExceptionColumnNumber=26, WKJavaScriptExceptionSourceURL=about:blank, NSLocalizedDescription=A JavaScript exception occurred}