How do I use XMLHttpRequest in Typescript?

typescript xmlhttprequest

The reason you can't specify this is because you are using an arrow function =>. You just need to change the type of the parameter:

request.onerror = (e: ProgressEvent) => {}

You don't really need to specify the type at all as it is inferred based on the type of onerror

request.onerror = (e) => {    e // is  ProgressEvent}

If you use a regular function you can specify this

request.onerror = function(this: XMLHttpRequest, e: ProgressEvent) {     this // is XMLHttpRequest}

Although you don't really need to as it will be implicitly typed based on the type of onerror

request.onerror = function(e: ProgressEvent) {     this // is still XMLHttpRequest}

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