post blob to google cloud storage

Iam trying to upload a file to the Google Cloud via JavaScript.
But but right now i’m failing miserably.

This is my Code so far:

 function uploadFile(){

    const file = document.querySelector('input[type=file]').files[0];
    const reader = new FileReader();
    let blob;
    reader.onload = function(e) {
        console.log(file)
        blob = new Blob([new Uint8Array(e.target.result)], {type: file.type });

        fetch('https://storage.googleapis.com/upload/storage/v1/b/"my_bucket_here"/o', {
            method: 'POST',
            headers: {
                'Content-Type': 'application/json',
                'Authorization': 'Bearer "Token here"'
            },
            body: blob,
        })
            .then(response => console.log('Success'))
            .catch(error => console.log(error));
    };
    reader.readAsArrayBuffer(file);

}

  1. At first I try to get the Token from my input tag in my html File

    const file = document.querySelector('input[type=file]').files[0];

Html:

    <input type="file" id="upload" name="upload" class="box">
  1. Then I have the reader.onload function where I store the File into a Blob

the logging of the File shows me the selectet File so the Code where i get my File should work….

  1. After that Iam trying to Post my Blob via fetch Api to my bucket

I think this is the point where the Code fails, because I get an 400 Http Error.

POST https://storage.googleapis.com/upload/storage/v1/b/yaec_example/o 400
reader.onload @ upload.js:11
load (async)
uploadFile @ upload.js:7
onclick @ index.html?_ijt=v0tmlt6ecn7lbgsgmve0d34dra:49

It would be great if someone experienced in Google Cloud Upload could help me…

Thanks!