export type DevMessage = (check: boolean, message: string) => void; let warning: DevMessage = () => {}; let invariant: DevMessage = () => {}; if (process.env.NODE_ENV !== 'production') { warning = (check, message) => { if (!check && typeof console !== 'undefined') { console.warn(message); } }; invariant = (check, message) => { if (!check) { throw new Error(message); } }; } export { warning, invariant };