let obj = { a: 4, b: 0.5 , c: 0.35, d: 5 };
let arr = Object.values(obj);
let min = Math.min(...arr);
let max = Math.max(...arr);
console.log( `Min value: ${min}, max value: ${max}` );
_x000D_
Try this:
let obj = { a: 4, b: 0.5 , c: 0.35, d: 5 };
var arr = Object.keys( obj ).map(function ( key ) { return obj[key]; });
and then:
var min = Math.min.apply( null, arr );
var max = Math.max.apply( null, arr );
Live demo: http://jsfiddle.net/7GCu7/1/