文件阅读器读取Blob文件

Question

i am trying to use filereader to access a blob file located locally, such as c drive, then converts it back to object URL as img src. it is not working, can anyone help this?

never found anyone try to access a blob file from disk. what is the blob file type extension?

const imageOut = document.querySelector('#image-out');

    imageOut.addEventListener('load', () => {
        const reader = new FileReader();

        reader.addEventListener('load', () => {

            var f = File.createFromFileName("file:///C:/blob.blb"); 

              const arrayBuffer = reader.readAsArrayBuffer(f);

            const blob = new Blob([arrayBuffer], { type: mimeType });

            imageOut.src = URL.createObjectURL(blob);

        });
    });

empty, not show

Answer 1

Check how to use blob here it is clearly explained and it should be enough to get you going.

Try this: Assuming that file:///C:/blob.blb exists and you are sure, then do it like so:

    imageOut.addEventListener('load', () => {
        const reader = new FileReader();
        var f = File.createFromFileName("file:///C:/blob.blb");
        reader.addEventListener('load', (e) => {
              const arrayBuffer = reader.readAsArrayBuffer(f);

            global.blob = new Blob([arrayBuffer], { type: f.type});

        });
// notice this is outside the reader Load.

var intval = setInterval(function(){
      if(blob !== undefined){
         imageOut.src = URL.createObjectURL(blob);  
         clearInterval(intval);
      }
     }, 100);

    });

I hope it helps.