Writes a message to the console with the visual "warning" icon and yellow background and a hyperlink to the line where it was called.
console.warn(object[, object, ...])
Object to output in the console. This can be any kind of object. The first argument to log may be a string containing
printf-like string substitution patterns. The complete list of patterns can be seen at console.log.
console.warn("This is some warning message.");