JSFiddle - React, Tailwind, and code Playground

HTML

<div id="d1"></div>

JavaScript

$.fn.plugin = function( options ) {
    
    console.log( $.type( options ) );
    
    if( $.type( options ) == 'string' ) {
        // Handle string case (first of above)
    }
    else if( $.type( options ) == 'object' && options != null ) {
        // Handle object case (second of above)
    }
    else {
        // Handle invalid input format
    
    }
    
};

$("#d1").plugin( new String('test')); //string
$("#d1").plugin('test'); //string
$("#d1").plugin({'key' : 'value'}); //object