getType

type.js

function getType (value) {
  let type = typeof value;
  if (type === 'object') {
    return value ? Object.prototype.toString.call(value).slice(8, -1) : 'null';
  }
  return type;
}

[NaN, 0, 1, Infinity,             // numbers
 null, undefined, false, 'str',   // other primitives
 new String('a'), new Boolean(true), // wrapped primitives
 {}, [], new Map, new WeakSet(),  // containers
 /regex/, new Date(),             // other custom objects
 window, navigator,               // native objects
 function () {}, (() => {}), atob,// functions
 Symbol(),                        // symbol
 {[Symbol.toStringTag]: 'Custom'} // @@ToStringTag
].map(getType);
// and the result is 
[
 "number", "number", "number", "number",  // numbers
 "null", "undefined", "boolean", "string",// other primitives
 "String", "Boolean",                     // wrapped primitives - notice the uppercase
 "Object", "Array", "Map", "WeakSet",     // containers
 "RegExp", "Date",                        // other custom objects
 "Window", "Navigator",                   // native objects
 "function", "function", "function",      // functions
 "symbol",                                // symbol
 "Custom",                                // @@ToStringTag
];

exotic objects like window & navigator return "Object" in pre-es5 engines (mostly IE8 and below)

I'd better use type-detect instead. It's faster.