如何在本地存储中保存数组

Question

I currently have this code, it saves in localstorage, but it generates several objects, I would like to store everything in a single array

getItemById(id) {
return this.cacheS.getOrSetCache(`StoreService_getItemById_${id}_${this.layout.emp.id}`, this.http.get(`${environment.API_URL}item/getById/${id}`), 300000);
}

  getOrSetCache(key: string, request: Observable<any>, msToExpire = 3600000): Observable<any> {
let cache: any = {};

cache = JSON.parse(localStorage.getItem(key));

return (cache?.data && (cache?.exp > Date.now())) ?
  of(cache.data) :
  request.pipe(tap(v => {
    localStorage.setItem(key, JSON.stringify({data: v, exp: (Date.now() + msToExpire)}));
  }));
}

This code works, but I wanted to join all the StoreService_getItemById_ , with this code it makes the array in a single StoreService_getItemById_ , if you notice the image has several local storage with the name StoreService_getItemById_, I would like it to have only one and inside that it had the objects in array format

        localStorage.setItem(key, JSON.stringify({data: [v], exp: (Date.now() + msToExpire)}));

I wish it were the same "item"

Answer 1

It sounds like you want to append items to an array in local storage. The thing is, local storage only saves strings . You can parse the string to convert it into an array, append a new item, then overwrite the old string.

const key = 'my-array-key';
const someData = { name: 'name', id: 'abcdef' };
const msToExpire = 5000;

// Convert string to array, initializes empty array if string is empty
let arr: any[] = [];
let string = localStorage.getItem(key);
if (string) arr = JSON.parse(string);

// Push a new item and overwrite the old string
arr.push({data: someData, exp: (Date.now() + msToExpire)});
localStorage.setItem(key, JSON.stringify(arr));

I'm not really sure how you want to structure that function but this example should give you the general idea.