在JavaScript中链接一个函数? [英] Chaining a function in JavaScript?
问题描述
我想创建一个将项目添加到我的localStorage对象的函数。例如:
alert(localStorage.getItem('names')。addItem('Bill')。getItem('names') );
第一种方法是getItem,它获取localStorage对象的项目...但addItem是一个自定义功能。这个函数链最终会提醒Bill。
那么,我该如何将这个函数链设置为localStorage?
但是,我做了一个可能的实现。
但是 getItem 会打破链(所以它应该总是在最后使用)。
storage()。setItem('names','Bill' ).getItem( '姓名'); //或
storage()。setItem('names')。addItem('Bill')。getItem('names'); //或
storage()。key('names')。value('Bill')。set()。get('names');
执行
< pre $ (function(window,undefined){
var storage = function(key,value){
return new storage.init(key,value );
};
storage.init = function(key,value){
this._key = key;
this._value = value;
};
storage.init.prototype = {
key:function(key){
this._key = key;
return this;
},
value:函数(value){
this._value = value;
返回this;
},
get:function(key){
key = isset(key)|| this._key;
返回localStorage.getItem(key);
},
set:function(key,value){
this._key = key = isset(key)|| this._key;
this._value = value = isset(value)|| this._value;
if(key& value){
localStorage.setItem(key,value);
}
return this;
},
addItem:function(value){
this._value = isset(value)|| this._value;
if(this._key&& value!== undefined){
localStorage.setItem(this._key,value);
}
返回此;
},
//别名...
getItem:function(key){
return this.get(key);
},
setItem:function(key,value){
return this.set(key,value);
}
};
函数isset(value){
返回值!== undefined?值:false;
}
window.storage = storage;
})(window);
I want to make a function that add an item to my localStorage object. E.g.:
alert(localStorage.getItem('names').addItem('Bill').getItem('names'));
The first method is getItem which gets the item for localStorage objects... but addItem would be a custom function. This chain of functions would finally alert Bill.
So, how would I make this function chain to localStorage?
This is possible if you create a wrapper/decorator object that makes chaining possible. This is how jQuery works for example. But it is useless in this case.
I made a possible implementation, though.
But getItem will break the chain (so it should always be used at the end).
storage().setItem('names', 'Bill').getItem('names'); // or
storage().setItem('names').addItem('Bill').getItem('names'); // or
storage().key('names').value('Bill').set().get('names');
Implementation
(function( window, undefined ) {
var storage = function( key, value ) {
return new storage.init( key, value );
};
storage.init = function( key, value ) {
this._key = key;
this._value = value;
};
storage.init.prototype = {
key: function( key ) {
this._key = key;
return this;
},
value: function( value ) {
this._value = value;
return this;
},
get: function( key ) {
key = isset(key) || this._key;
return localStorage.getItem( key );
},
set: function( key, value ) {
this._key = key = isset(key) || this._key;
this._value = value = isset(value) || this._value;
if ( key && value ) {
localStorage.setItem( key, value );
}
return this;
},
addItem: function( value ) {
this._value = isset(value) || this._value;
if ( this._key && value !== undefined ) {
localStorage.setItem( this._key, value );
}
return this;
},
// aliases...
getItem: function( key ) {
return this.get( key );
},
setItem: function( key, value ) {
return this.set( key, value );
}
};
function isset( value ) {
return value !== undefined ? value : false;
}
window.storage = storage;
})( window );
这篇关于在JavaScript中链接一个函数?的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!