Javascript 角度2本地存储密钥
我正在使用本地存储。在构造函数中,我已经完成了:Javascript 角度2本地存储密钥,javascript,html,angular,local-storage,Javascript,Html,Angular,Local Storage,我正在使用本地存储。在构造函数中,我已经完成了: this.currentData=(localStorage.getItem('currentData')!==null)?parse(localStorage.getItem('currentData')):[] 但这样做我会将数据存储在数组中,我认为这不好 所以,我做到了: constructor(){ if(this.currentData !== null && this.currentData !== undefine
this.currentData=(localStorage.getItem('currentData')!==null)?parse(localStorage.getItem('currentData')):[]代码>
但这样做我会将数据存储在数组中,我认为这不好
所以,我做到了:
constructor(){
if(this.currentData !== null && this.currentData !== undefined) {
for (var i = this.currentData.length - 1; i >= 0; i--) {
this.currentData = JSON.parse(localStorage.getItem('currentData-' + i));
console.log('currentData if:' + this.currentData)
}
} else {
console.log('currentData else:' + this.currentData)
}
}
但我得到一个错误,TypeError:无法读取未定义的属性'length'
TypeError:无法读取未定义的属性“length”
要保存数据,请执行以下操作:
saveLocalStorage(todo){
this.objects.push(todo);
for (var i = this.objects.length - 1; i >= 0; i--) {
localStorage.setItem('currentData-' + i, JSON.stringify(this.objects[i]));
}
}
如何从localStorage获取倍数数据?
有人知道我如何解决这个问题吗?您应该使用注入构造函数的localstorage
您可能忘记了下面的关键字
this.currentData = (this.localStorage.getItem('currentData')!==null) ? JSON.parse(localStorage.getItem('currentData')) : [ ];
或者,您可以使用as
user:any[]={name:'abc',id:1};
valuFromLocalStorage:any{};
constructor(private localStorageService: LocalStorageService) {
this.name = 'Angular2';
this.localStorageService.add('a',this.user);
console.log(this.localStorageService.get('a'));
this.valuFromLocalStorage= this.localStorageService.get('a')
}
我做了一个服务来处理本地存储。也许这可以帮助你:
import { Injectable } from '@angular/core';
@Injectable()
export class NpStorageService {
constructor(){
this.checkIflocalStorageIsAvailable();
}
private checkIflocalStorageIsAvailable = () => {
let type = '';
try {
let testKey = '__np_storage_test__' + Date.now();
type = 'localStorage';
localStorage.setItem(testKey, 'work');
localStorage.removeItem(testKey);
type = 'sessionStorage';
sessionStorage.setItem(testKey, 'work');
sessionStorage.removeItem(testKey);
return true;
}
catch(e) {
console.error('NpStorageService => Cannot find ' + type + ' on this browser.');
return false;
}
}
get = (key?: string) => {
return JSON.parse(localStorage.getItem(key));
}
set = (key: string, value: any): boolean => {
try {
localStorage.setItem(key, JSON.stringify(value));
return true;
}
catch(e) {
return false;
}
}
remove = (key: string) => {
return localStorage.removeItem(key);
}
}
使用$localStorage服务
它允许您轻松地与localStorage对象交互,并在数据更改时调用摘要
您可以像这样轻松地添加/删除变量
$localStorage.myObject = {array: [1,2,3,4]};
如果您只是console.log它,那么this.currentData包含什么?您应该像这样实现for循环以便于理解:for(var i=0;i>this.objects.length;i--)谢谢您的回答,我正在将localstorage
用于构造函数。我会根据你的答案更新代码,我会模拟数据,但我做不到。当我在localstorage中插入一个新数据时,这个新数据需要有一个唯一的localstorage键谢谢你的回答,但我没有使用AngularJS,我使用的是Angular2。谢谢,我会尝试使用它