node.js - How can a javascript function also be an object? -

this tough 1 word, how can have model.method() , model() valid @ same time? particular library makes me ask mongoose (http://mongoosejs.com/docs/) model object represents mongo collection , has several methods , model function constructor mongo document methods. i'm trying similar, returns function making typeof model === 'function' , never object. follows:

let model = (function(){         for(var in queries){             if(typeof == 'function'){                 if(i == 'insert'){                     continue;                 }                 this[i] = function(){                     queries[i].apply(this, arguments); // queries separate module i've written has methods querying db                 };             }         }         return (function(){             for(var in arguments[0]){                 if(!(i in schema) && typeof arguments[0][i] != typeof schema[i]){                     this[i] = arguments[0][i];                 }                 else{                     throw new error('invalid argument, key: ' + + ' value: ' + arguments[0][i]);                 }             }             for(var in schema.methods){                 this[i] = schema.methods[i];             }         });     })(); 

all javascript functions objects. that's how javascript works.

function alert(message) {      document.body.appendchild(document.createtextnode(message));      document.body.appendchild(document.createelement('br'));  }    function myfunction() {    alert("this myfunction");  }    myfunction.property = "hello";    myfunction.recursive = myfunction;    myfunction();  alert(myfunction.property);  alert(myfunction.name);  myfunction.recursive.recursive.recursive.recursive.recursive();