I have an angular file upload component, where I want to get the base64 and save it. So far it works, but my base64 starts like this:

"data:application/pdf;base64,JVBERi0xLjQKJfbk/N8KM......."

is there anyway to only get the code and not the data:application/pdf;base64 etc.

Here is my code:

  uploadFile(files: FileList | null): void {
      if(files){
        const file = files.item(0)
        const reader = new FileReader()
        reader.readAsDataURL(file)
        reader.onload = () => {
        this.documentsArray.push({documentType: this.form.controls.dokumentType.value, fileBase64: reader.result,fileName: file.name})
        console.log(this.documentsArray)
        }
      }
    }