JavaScript object manipulation
This lesson is to talk:
- JavaScript object creation
- JavaScript Object basic operations
- JavaScript function object
Speaker teachers: Head teacher
Two. JavaScript Object basic operations
1. traversing members
for(sx in p){
console.log(sx);
console.log(p[sx]);
}
// attributes are unordered
Object.keys(p) ;
Returns an array of sort.
2. The members of the traversal View
Object .hasOwnProperty ( "attribute name") if it returns true itself, if it is inherited return false
3. Delete members
delete p.name
4. Members of the learning characteristics
Object.getOwnPropertyDescriptor (Object, "property name") characteristics or properties of the object was
1.configurable, whether the property is configurable. Meaning Configurable include: whether the property can be deleted (delete), whether or not you can modify the properties of the writable, enumerable, configurable attribute.
2.enumerable, property is enumerable. Enumerable meanings include: Is it possible to traverse through for ... in, is it possible method to obtain property by name Object.keys ().
3.writable, whether the property can be rewritten. Rewritable meanings include: whether the property can be re-assigned.
4.value, the default value of the property.
5.set, Rewriter property (for the time being so called). Once the property is re-assigned, this method is called automatically.
6.get, reader attributes (for the time being so called). Once the property is accessed read, this method is called automatically.
5. The the Constructor Constructor
A built-in property belonging to the object, to point to create this object constructor
Statement of the nature of the object is no different in two ways
There o = {};
var o1 = new Object{}；
a. Constructor === O1. constructor ;
number. Constructor；
function f(){}
f. Constructor
function. Constructor
1. Constructor
V R = 1;
to. constructor ;
6. Type checking
typeo of operator
Returns a string representation, indicates what type it is
such as:
typeof "a" returns the string
typeof null returns an object. This is a mistake javascript language itself, in order to be compatible has been no change, it should return null son.
typeof undefined返回undefined
instanceof instance of a constructor
o instanceof object
o instanceof o. Constructor
8. constructor to create objects using
Var o = {name:“abc”}；
V would O1 = a. Constructor
O 1.name // o1 create a new object, rather than copying the o.