declare var global: any; let root: any; if (typeof self !== 'undefined') { root = self; } else if (typeof window !== 'undefined') { root = window; } else if (typeof global !== 'undefined') { root = global; } else { root = Function('return this')(); } const Symbol = root.Symbol; let parentSymbol: symbol; if (typeof Symbol === 'function') { parentSymbol = Symbol('parent'); } else { parentSymbol = '@@snabbdom-selector-parent' as any; } export default parentSymbol;