opencv.js load image in react, cv.imencode is undefined

Hello I want to manipulate an image in react. So I use opencv.js for this. I found this repo https://github.com/vinissimus/opencv-js-webworker which gives a good example how to use it with react. In this example the image was loaded from a canvas. But I have a blob or a normal image. I dont know how to load this image in opencv.js. I was able to transform the image to base64 string. But I dont know how to load then the base64 string with opencv.js. I found this question here https://answers.opencv.org/question/215404/reading-data-uri-with-opencvjs/, where the answer says to use cv2.imencode to load base64 image. I am using latest opencv.js and cv.imencode is undefined. How can I solve this problem? Is cv.imencode avaiable in some older releases? Maybe somebody has an other workaround to use it with react (create-react-app)?