JSFiddle - React, Tailwind, and code Playground

JavaScript

var obj = { a: 4, b: 0.5 , c: 0.35, d: 5 };

var arr = Object.keys( obj ).map(function ( key ) { return obj[key]; });
var min = Math.min.apply( null, arr );
var max = Math.max.apply( null, arr );

document.write( 'Min value: ' + min + ', max value: ' + max );