Extract to constant in enclosing scope should optionally also replace later usage

Given this code:

	public setParts(lineNumber: number, parts: GhostTextPart[]): void {
		const foreground = this.themeService.getColorTheme().getColor(ghostTextForeground);
		let opacity: string | undefined = undefined;
		let color: string | undefined = undefined;
		if (foreground) {


			opacity = String(foreground.rgba.a);
			color = Color.Format.CSS.format(opaque(foreground))!;
		}

		const borderColor = this.themeService.getColorTheme().getColor(ghostTextBorder);
		let border: string | undefined = undefined;
		if (borderColor) {
			border = `2px dashed ${borderColor}`;
		}

I would like to factor our this.themeService.getColorTheme() and extract it into its own constant. This should include all later usages.
Since there could be side effects in between, I suggest to do it only if later occurences are also selected.

This is my current workflow and I don't feel smart doing it like that. Multicursors don't really help here.

Also, it would be nice if the name of the new local is heuristically derived from the expression ((...).getFooBar(...) -> fooBar`).

I'm willing to do a PR if I get some pointers.

Let's make the editing experience in VS Code even more amazing 😉

Start by locating the extract-to-constant refactoring implementation and its tests in the TypeScript repository. Reproduce the shown TypeScript example, then trace how selection boundaries and later occurrences are handled. Done means an optional enclosing-scope extraction can include later uses only when selected, with heuristic naming considered separately.