ES5 Object.create 方法

var o;// create an object with null as prototype
o = Object.create(null);o = {};
// is equivalent to:
o = Object.create(Object.prototype);function Constructor() {}
o = new Constructor();
// is equivalent to:
o = Object.create(Constructor.prototype);
// Of course, if there is actual initialization code
// in the Constructor function,
// the Object.create() cannot reflect it// Example where we create an object with a couple of
// sample properties. (Note that the second parameter
// maps keys to *property descriptors*.)
o = Object.create(Object.prototype, {
// foo is a regular 'value property'
foo: {
writable: true,
configurable: true,
value: 'hello'
},
// bar is a getter-and-setter (accessor) property
bar: {
configurable: false,
get: function() { return 10; },
set: function(value) {
console.log('Setting `o.bar` to', value);
}
/* with ES5 Accessors our code can look like this
get function() { return 10; },
set function(value) {
console.log('Setting `o.bar` to', value);
} */
}
});// Create a new object whose prototype is a new, empty
// object and add a single property 'p', with value 42.
o = Object.create({}, { p: { value: 42 } });// by default properties ARE NOT writable,
// enumerable or configurable:
o.p = 24;
o.p;
//o.q = 12;
for (var prop in o) {
console.log(prop);
}
// 'q'delete o.p;
// false// to specify an ES3 property
o2 = Object.create({}, {
p: {
value: 42,
writable: true,
enumerable: true,
configurable: true
}
});

if (typeof Object.create != 'function') {
Object.create = (function(undefined) {
var Temp = function() {};
return function (prototype, propertiesObject) {
if(prototype !== Object(prototype)) {
throw TypeError(
'Argument must be an object, or null'
);
}
Temp.prototype = prototype || {};
var result = new Temp();
Temp.prototype = null;
if (propertiesObject !== undefined) {
Object.defineProperties(result, propertiesObject);
} // to imitate the case of Object.create(null)
if(prototype === null) {
result.__proto__ = null;
}
return result;
};
})();
}