What does the JavaScript "Object" function do?

What does the Object function in JavaScript do?

开发者_JAVA百科For example, what happens when we do Object(1)?

It forces something to be an object. I've not seen it being used in this way though.

var num = 1;
var obj = Object(num);
alert(typeof num); //displays "number"
alert(typeof obj): //displays "object"
alert(num + "," + obj); //displays "1,1"

The preferred, faster way to create an empty object on which you can put properties and methods on is by using {}. Three possible ways to create an object:

var emptyObj = {};
var emptyObj = new Object();
var emptyObj = new Object; // Object does not need an argument, so this is valid.

From the Mozilla developer site:

The Object constructor creates an object wrapper for the given value. If the value is null or undefined, it will create and return an empty object, otherwise, it will return an object of type that corresponds to the given value.

When called in a non-constructor context, Object behaves identically.

So Object(1) produces an object that behaves similarly to the primitive value 1, but with support for object features like assigning values to properties (Object(1).foo = 2 will work, (1).foo = 2 will not).

var obj = Object("test");

Creates a String "text", it's pretty similar to

var obj2 = "test";

Notice that the type of obj2 is "String" and of obj1 "Object"

Try this:

 <script>
var obj = Object("test");
console.log(obj);
console.log(typeof(obj));
console.log(obj["0"]);

obj2 = "test";
console.log(obj2);
console.log(typeof(obj2));
console.log(obj2["0"]);

</script>

Creates an object http://www.w3schools.com/js/js_objects.asp

Object function is a constructor function, all other types(like Array, String, Number) inheritate it.