如何解决错误，无法使用amcharts4的exportmenu.draw读取null的属性推送？

Question

在一页中，我们正在加载amcharts4 mapcharts，折线图和饼图以及大量数据。当页面地图的onload加载不正确并且在浏览器控制台中时，它会抛出许多控制台错误。

这里有错误

zone.js:199 Uncaught TypeError: Cannot read property 'push' of null
    at ExportMenu.push../node_modules/@amcharts/amcharts4/.internal/core/export/ExportMenu.js.ExportMenu.draw (ExportMenu.js:209)
    at ExportMenu.push../node_modules/@amcharts/amcharts4/.internal/core/export/ExportMenu.js.ExportMenu.validate (ExportMenu.js:171)
    at Object.dispatch (EventDispatcher.js:381)
    at EventDispatcher.js:266
    at Module.each (Array.js:74)
    at EventDispatcher.push../node_modules/@amcharts/amcharts4/.internal/core/utils/EventDispatcher.js.EventDispatcher._eachListener (EventDispatcher.js:239)
    at EventDispatcher.push../node_modules/@amcharts/amcharts4/.internal/core/utils/EventDispatcher.js.EventDispatcher.dispatchImmediately (EventDispatcher.js:264)
    at Registry.push../node_modules/@amcharts/amcharts4/.internal/core/Registry.js.Registry.dispatchImmediately (Registry.js:209)
    at System.push../node_modules/@amcharts/amcharts4/.internal/core/System.js.System.update (System.js:299)
    at System.js:343

当我们尝试注释掉图表组件中的以下行时，它不会抛出错误，但是会丢失导出功能

if (chartConfig.export && chartConfig.export.enabled) {
      newChart.exporting.menu = new am4core.ExportMenu();
      newChart.exporting.menu.verticalAlign = chartConfig.export.valign as am4core.VerticalCenter;
      newChart.exporting.menu.align = chartConfig.export.halign as am4core.Align;
}

那么导致这些错误的原因是什么，如何解决这些错误并保持导出功能呢？

Answer 1

直到amCharts 4版本4.7.5为止，我都有相同的错误，在撰写本文时，我已更新至版本4.7.12，此问题已解决。

我的建议是，截至2019年12月5日，现在使用最新版本的amCharts即4.7.12升级package.json文件，这将解决您的问题。