New Typescript 1.8.4 build error: " Build: Property 'result' does not exist on type 'EventTarget'. "
Instead of using event.target.result
, you can just use FileReader.result
.
For example,
const fileReader: FileReader = new FileReader();
fileReader.onload = (event: Event) => {
event.target.result; // This is invalid
fileReader.result; // This is valid
};
While any
is a medicine (almost for anything, but... where is the TypeScript benefit then)... there is a similar issue reported and nice (TypesScript-ish) workaround suggested
Request to change currentTarget in Event interface for lib.d.ts
let me cite:
I ran into this TS2339: Property 'result' does not exist on type 'EventTarget' in JS FileReader onload, and another warning for getSummary() on the event passed to FileReader's onerror.
My work-around, to suppress the horrid red squiggily lines;-) is the following:
interface FileReaderEventTarget extends EventTarget { result:string } interface FileReaderEvent extends Event { target: FileReaderEventTarget; getMessage():string; }
Then in my app:
reader.onload = function(fre:FileReaderEvent) { var data = JSON.parse(fre.target.result); ... }
And, until some change in lib.d.ts, we still do work with known interface
EDIT Dec 2019:
With this fix, you might be getting
error TS2322: Type '(this: FileReader, e: FileReaderEvent) => void' is not assignable to type '(this: FileReader, ev: ProgressEvent) => any'.
If so, just replace
interface FileReaderEvent extends Event {
with
interface FileReaderEvent extends ProgressEvent {
With my old type script the parameter "imgsrc" is having any type by default.
So, now I made it as (imgsrc:any). It's working fine.
var reader:any,
target:EventTarget;
reader= new FileReader();
reader.onload = function (imgsrc:any){
var fileUrl = imgsrc.target.result;
}