这个问题通常出现在使用ngrx-store-localstorage插件时,在localStorage中存储了map类型的数据,并尝试将其恢复为映射,但会遇到问题。
解决办法是,在使用ngrx-store-localstorage插件时,存储的数据应为一个普通的JavaScript对象,而不是一个map。此外,在将对象存储到localStorage中之前,应将其转换为JSON字符串,以确保存储在localStorage中的对象格式正确。然后,在将localStorage中的数据恢复为对象时,应使用JSON.parse解析并转换为JavaScript对象。
示例:
在将对象存储到localStorage之前,使用JSON.stringify将其转换为JSON字符串:
import { State } from './state';
import { LocalStorage } from 'ngrx-store-localstorage';
export function storageMetaReducer(reducer: ActionReducer): ActionReducer {
return localStorageSync({
keys: ['module1', 'module2'],
rehydrate: true,
storage: localStorage,
transform: (state: State) => {
return { ...state };
}
})(reducer);
}
在将localStorage中的数据恢复为对象时,使用JSON.parse将其解析为JavaScript对象:
import { State } from './state';
import { LocalStorage } from 'ngrx-store-localstorage';
export function storageMetaReducer(reducer: ActionReducer): ActionReducer {
return localStorageSync({
keys: ['module1', 'module2'],
rehydrate: true,
storage: localStorage,
parse: JSON.parse,
mergeReducer: true,
transform: (state: State) => {
return { ...state };
}
})(reducer);
}