JSFiddle - React, Tailwind, and code Playground

JavaScript

var a = [ 'Istanbul', 'Hong Kong', 'Berlin' ];
var b = [ 'Berlin', 'Bonn' ];

var minus = function ( a, b ) {
    return a.filter(function ( name ) {
        return b.indexOf( name ) === -1;
    });
};
                    

var result = minus( a, b );
    
document.write( result );