src/vs/editor/contrib/find/browser/findDecorations.ts/FindDecorations/getFindScopes
class FindDecorations:	public getFindScopes(): Range[] | null {
		if (this._findScopeDecorationIds.length) {
			const scopes = this._findScopeDecorationIds.map(findScopeDecorationId =>
				this._editor.getModel().getDecorationRange(findScopeDecorationId)
			).filter(element => !!element);
			if (scopes.length) {
				return scopes as Range[];
			}
		}
		return null;
	}