cv.QRCodeDetector is not a function

error:
``` js
const qrDecoder = cv.QRCodeDetector()
^

TypeError: cv.QRCodeDetector is not a function
at Object. (e:\auto\auto-control\test.js:8:22)
at Module._compile (internal/modules/cjs/loader.js:776:30)
at Object.Module._extensions..js (internal/modules/cjs/loader.js:787:10)
at Module.load (internal/modules/cjs/loader.js:653:32)
at tryModuleLoad (internal/modules/cjs/loader.js:593:12)
at Function.Module._load (internal/modules/cjs/loader.js:585:3)
at Function.Module.runMain (internal/modules/cjs/loader.js:829:12)
at startup (internal/bootstrap/node.js:283:19)
at bootstrapNodeJSCore (internal/bootstrap/node.js:622:3)
```

code:
```js
const cv = require('opencv4nodejs');
const inputImage = cv.imread("xxx.jpg")
const qrDecoder = cv.QRCodeDetector()
```