keyof T should never print as a union of strings

TypeScript Version: 3.6.2

Search Terms: extends keyof generic

Code

export const bindEvent = <Node extends HTMLElement | HTMLDocument,
	K extends keyof HTMLElementEventMap>(
	node: Node,
	type: K,
	callback: (event: HTMLElementEventMap[K]) => unknown,
) => {
	node.addEventListener(type, callback as EventListener);

	return () => {
		node.removeEventListener(type, callback as EventListener);
	};
};

tsc

Expected behavior:
The generic K to still be extends keyof, instead of spreading the type out.

Actual behavior:
types generated:

export declare const bindEvent: <Node_1 extends HTMLElement | HTMLDocument, K extends "fullscreenchange" | "fullscreenerror" | "abort" | "animationcancel" | "animationend" | "animationiteration" | "animationstart" | "auxclick" | "blur" | "cancel" | "canplay" | "canplaythrough" | "change" | "click" | "close" | "contextmenu" | "cuechange" | "dblclick" | "drag" | "dragend" | "dragenter" | "dragexit" | "dragleave" | "dragover" | "dragstart" | "drop" | "durationchange" | "emptied" | "ended" | "error" | "focus" | "focusin" | "focusout" | "gotpointercapture" | "input" | "invalid" | "keydown" | "keypress" | "keyup" | "load" | "loadeddata" | "loadedmetadata" | "loadend" | "loadstart" | "lostpointercapture" | "mousedown" | "mouseenter" | "mouseleave" | "mousemove" | "mouseout" | "mouseover" | "mouseup" | "pause" | "play" | "playing" | "pointercancel" | "pointerdown" | "pointerenter" | "pointerleave" | "pointermove" | "pointerout" | "pointerover" | "pointerup" | "progress" | "ratechange" | "reset" | "resize" | "scroll" | "securitypolicyviolation" | "seeked" | "seeking" | "select" | "selectionchange" | "selectstart" | "stalled" | "submit" | "suspend" | "timeupdate" | "toggle" | "touchcancel" | "touchend" | "touchmove" | "touchstart" | "transitioncancel" | "transitionend" | "transitionrun" | "transitionstart" | "volumechange" | "waiting" | "wheel" | "copy" | "cut" | "paste">(node: Node_1, type: K, callback: (event: HTMLElementEventMap[K]) => unknown) => () => void;

Es wird keine Repository-Datei oder kein Testpfad erwähnt. Reproduziere das Problem mit dem bereitgestellten Snippet und TypeScript 3.6.2 und verfolge anschließend die Generierung von Deklarationen und die Typausgabe, um festzustellen, an welcher Stelle die generische Einschränkung erweitert wird. Als erledigt gilt die Aufgabe, wenn die generierte Deklaration K weiterhin als Erweiterung von keyof HTMLElementEventMap beibehält, anstatt die Vereinigung der Ereignisnamen auszugeben.