TypeError: undefined is not an object (evaluating 'f.navigator') __ERROR

ios page loading file-saver error message, such as question, page white screen can not load, please ask how to solve? The specific code is as follows:
```html

import domtoimage from 'dom-to-image'
import fileSaver from 'file-saver'

export default {
methods: {
shotPic() {
let node = document.getElementById('my-node');

domtoimage.toBlob(node, { quality: 1.0}).then(function (blob) {
fileSaver.saveAs(blob, 'my-node.png');
});
}
},
components: {
domtoimage,
fileSaver
}
}

```
package.json：
```json
"dependencies": {
"dom-to-image": "^2.6.0",
"file-saver": "^2.0.5",
"vue-qr": "^4.0.9"
}
```