convert image path to base64 typescript

1var xhr = new XMLHttpRequest();       
2    xhr.open("GET", "/path/to/local/image/file", true); 
3    xhr.responseType = "blob";
4    xhr.onload = function (e) {
5            console.log(this.response);
6            var reader = new FileReader();
7            reader.onload = function(event) {
8               var res = event.target.result;
9               console.log(res)
10            }
11            var file = this.response;
12            reader.readAsDataURL(file)
13    };
14    xhr.send()