declare const process ; const isProduction = process . env . NODE_ENV === "production" ; hidden param condition param message export function assert ( condition , message ? ) { if ( ! isProduction ) { if ( ! condition ) { throw new Error ( message !== undefined ? message : "ASSERTION failed" ) ; } } } export function assertExists < T > ( element , message ? ) { if ( ! isProduction ) { if ( element === undefined || element === null ) { throw new Error ( message !== undefined ? message : "ASSERTION failed: Element is undefined or null" ) ; } } return element ! ; }