html2canvas:未捕获错误( promise ):[对象未定义] angular 6

Question

我正在使用 html2canvas 将 html 转换为图像，然后导出为 pdf 文件。这是我使用这个包的步骤:

1. yarn 添加html2canvas

2. 添加代码以将 html 转换为图像。

   async export(comp, doc, save) {
     // create pdf file
     let height = REPORT_PAGE.top;
     const header = comp.reportHeader.nativeElement;
     const headerCanvas = await html2canvas(header, {svgRendering: true});
     height = REPORT_PAGE.top;
     let imgHeightHtml = REPORT_PAGE.header * REPORT_PAGE.width / headerCanvas.width;
     let contentDataURL = headerCanvas.toDataURL('image/png');
     doc.addImage(contentDataURL, 'PNG', REPORT_PAGE.left, height, REPORT_PAGE.width, imgHeightHtml);
     if (save) {
       doc.save('myreport.pdf');
     } else {
       doc.addPage();
     }
   }
   

其中 comp 是角度分量，doc 是 jsPDF，save 是 bool 值。调用html2canvas时会抛出如下错误。

Uncaught (in promise): [object Undefined]
at resolvePromise (zone.js:814)
at resolvePromise (zone.js:771)
at zone.js:873
at ZoneDelegate.push../node_modules/zone.js/dist/zone.js.ZoneDelegate.invokeTask (zone.js:421)
at Object.onInvokeTask (core.js:4053)
at ZoneDelegate.push../node_modules/zone.js/dist/zone.js.ZoneDelegate.invokeTask (zone.js:420)
at Zone.push../node_modules/zone.js/dist/zone.js.Zone.runTask (zone.js:188)
at drainMicroTaskQueue (zone.js:595)
at push../node_modules/zone.js/dist/zone.js.ZoneTask.invokeTask (zone.js:500)
at ZoneTask.invoke (zone.js:485)

html2canvas 是一个非常有用的包，但是这个错误真的很糟糕。请帮忙。

Answer 1

我遇到了同样的问题，这解决了它:

html2canvas(element, {
    ignoreElements: (node) => {
        return node.nodeName === 'IFRAME';
    }
}).then((canvas) => {
    ...
});

来源:https://github.com/niklasvh/html2canvas/issues/1593#issuecomment-489059452