I'm testing my React-Native application and want to remove all items from AsyncStorage in order to test the app from the beginning. And I am a bit confused.
I read the official documentation and found multiRemove and clear functions, but I cannot understand how to clear all items of my application (clear as far as I understood clear the whole storage of all applications and I'm afraid to use it),
and multiRemove delete only keys that I give it in parameters, but I want to clear all keys.
I suppose I can do it through getAllKeys keys-values and remove it one-by-one, but maybe there is a more clear way to do it? :)
thanks
P.S: I tried to to like this:
clearAllData() {
AsyncStorage.multiRemove([]).then(() => alert('success'));
}
but it doesn't work...
I suppose I can do it through getAllKeys keys-values and remove it one-by-one, but maybe there is a more clear way to do it? :)
You should do that, that's the only way to remove all keys from your app.
Here is a simple way of doing it:
clearAllData() {
AsyncStorage.getAllKeys()
.then(keys => AsyncStorage.multiRemove(keys))
.then(() => alert('success'));
}
When your app runs, it is assigned a unique ID. Each stored key is prefixed by the ID. Therefore, all YOUR app's keys can be identified.
Using AsyncStorage.clear does not use unique identifiers and will delete keys for all clients, apps, and libraries. This might be OK in development but probably undesirable in production.
Per #Bruno Soares, multiRemove is preferred. However, note that 'await' can only be used within an async function. Combining Bruno's answer with #Prawesh Panthi, the following function will delete keys that are only associated with your app without having to explicitly identify the keys.
removeAppKeys = async () => {
let keys = []
try {
keys = await AsyncStorage.getAllKeys()
console.log(`Keys: ${keys}`) // Just to see what's going on
await AsyncStorage.multiRemove(keys)
} catch(e) {
console.log(e)
}
console.log('Done')
}
removeFew = async () => {
const keys = ['#MyApp_USER_1', '#MyApp_USER_2']
try {
await AsyncStorage.multiRemove(keys)
} catch(e) {
// remove error
}
console.log('Done')
}
Here a way of doing it, using async/await:
const keys = await AsyncStorage.getAllKeys()
await AsyncStorage.multiRemove(keys)
Related
Here is a reproducable stackblitz -
https://stackblitz.com/edit/nuxt-starter-jlzzah?file=components/users.vue
What's wrong? -
My code fetches 15 items, and with the bottom scroll event it should fetch another 15 different items but it just fetches same items again.
I've followed this bottom video for this implementation, it's okay in the video but not okay in my stackblitz code:
https://www.youtube.com/watch?v=WRnoQdIU-uE&t=3s&ab_channel=JohnKomarnicki
The only difference with this video is that he's using axios while i use useFetch of nuxt 3.
It's not really a cache issue. useFetch is "freezing" the API URL, the changes you make to the string directly will not be reliably reflected. If you want to add parameters to your API URL, use the query option of useFetch. This option is reactive, so you can use refs and the query will update with the refs. Alternatively, you can use the provided refresh() method
const limit = ref(10)
const skip = ref(20)
const { data: users, refresh: refreshUsers } = await useFetch(
'https://dummyjson.com/users',
{
query:{
limit,
skip
}
}
);
//use the data object directly to access the result
console.log(users.value)
//if you want to update users with different params later, simply change the ref and the query will update
limit.value = 23
//use refresh to manually refresh the query
refreshUsers()
This results in a first API call http://127.0.0.1:8000/api/tasks?limit=10&skip=20 and then a second with the updated values http://127.0.0.1:8000/api/tasks?limit=23&skip=20
You can leave the cache alone, as it is just a workaround, and will not work reliably.
[Updated] The useFetch() documentation is now updated as described below.
The query option is not well documented yet, as discussed in this nuxt issue. I've created a pull request on nuxt/framework to have it reflected in the documentation. Please see a full explanation below:
Using the query option, you can add search parameters to your query. This option is extended from unjs/ohmyfetch and is using ufo to create the URL. Objects are automatically stringified.
const param1 = ref('value1')
const { data, pending, error, refresh } = await useFetch('https://api.nuxtjs.dev/mountains',{
query: { param1, param2: 'value2' }
})
This results in https://api.nuxtjs.dev/mountains?param1=value1¶m2=value2
Nuxt3's useFetch uses caching by default. Use initialCache: false option to disable it:
const getUsers = async (limit, skip) => {
const { data: users } = await useFetch(
`https://dummyjson.com/users?limit=${limit}&skip=${skip}`,
{
initialCache: false,
}
);
//returning fetched value
return users.value.users;
};
But you probably should use plain $fetch instead of useFetch in this scenario to avoid caching:
const getUsers = async (limit, skip) => {
const { users } = await $fetch(
`https://dummyjson.com/users?limit=${limit}&skip=${skip}`
);
//returning fetched value
return users;
};
I am working with Nuxt and Vue, with MySQL database, all of which are new to me. I am transitioning out of WebMatrix, where I had a single Admin page for multiple tables, with dropdowns for selecting a particular option. On this page, I could elect to add, edit or delete the selected option, say a composer or music piece. Here is some code for just 2 of the tables (gets a runtime error of module build failed):
<script>
export default {
async asyncData(context) {
let [{arrangers}, {composers}] = await Promise.all([
context.$axios.get(`/api/arrangers`),
context.$axios.get(`/api/composers`),
])
const {arrangers} = await context.$axios.get('/api/arrangers')
const {composers} = await context.$axios.get('/api/composers')
return { arrangers, composers }
},
}
</script>
You do have the same variable name for both the input (left part of Promise.all) and as the result from your axios call, to avoid naming collision, you can rename the result and return this:
const { arrangers: fetchedArrangers } = await context.$axios.get('/api/arrangers')
const { composers: fetchedComposers } = await context.$axios.get('/api/composers')
return { fetchedArrangers, fetchedComposers }
EDIT, this is how I'd write it
async asyncData({ $axios }) {
const [posts, comments] = await Promise.all([
$axios.$get('https://jsonplaceholder.typicode.com/posts'),
$axios.$get('https://jsonplaceholder.typicode.com/comments'),
])
console.log('posts', posts)
console.log('comments', comments)
return { posts, comments }
},
When you destructure at the end of the result of a Promise.all, you need to destructure depending of the result that you'll get from the API. Usually, you do have data, so { arrangers } or { composers } will usually not work. Of course, it depends of your own API and if you return this type of data.
Since destructuring 2 data is not doable, it's better to simply use array destructuring. This way, it will return the object with a data array inside of it.
To directly have access to the data, you can use the $get shortcut, which comes handy in our case. Directly destructuring $axios is a nice to have too, will remove the dispensable context.
In my example, I've used JSONplaceholder to have a classic API behavior (especially the data part) but it can work like this with any API.
Here is the end result.
Also, this is what happens if you simply use this.$axios.get: you will have the famous data that you will need to access to later on (.data) at some point to only use the useful part of the API's response. That's why I do love the $get shortcut, goes to the point faster.
PS: all of this is possible because Promise.all preserve the order of the calls: https://stackoverflow.com/a/28066851/8816585
EDIT2: an example on how to make it more flexible could be
async asyncData({ $axios }) {
const urlEndpointsToFetchFrom = ['comments', 'photos', 'albums', 'todos', 'posts']
const allResponses = await Promise.all(
urlEndpointsToFetchFrom.map((url) => $axios.$get(`https://jsonplaceholder.typicode.com/${url}`)),
)
const [comments, photos, albums, todos, posts] = allResponses
return { comments, photos, albums, todos, posts }
},
Of course, preserving the order in the array destructuring is important. It's maybe doable in a dynamic way but I don't know how tbh.
Also, I cannot recommend enough to also try the fetch() hook alternative someday. I found it more flexible and it does have a nice $fetchState.pending helper, more here: https://nuxtjs.org/blog/understanding-how-fetch-works-in-nuxt-2-12/ and in the article on the bottom of the page.
I created some example code underneath to show what I mean.
Is it okay to update some data after saving inside of a post route? I often update and save data in a single route, and I never know if it is okay to do this and if there are any consequences of the code that I am unaware of.
router.post('/sync-steam', auth, async(req, res) => {
const { steamID, steamName } = req.body
try {
await req.user.save( steamID )
await req.user.updateOne( steamName )
res.send("OK")
} catch(err) {
res.status(400).send(err)
}
})
Yes, it is OK to do that. There should not be any issues regarding that as long as your logic that communicates with your database is correct.
However, you should try to follow the convention of REST API, and use the correct method:
GET for listing/reading content
POST for creating content
PUT for replacing content
PATCH for updating part of the content
DELETE for deleting content
I am attempting to use Redux Observable to call an action to fetch some data, wait for its return, then fetch some more data that relies on it.
I have an epic which populates a store from a fetch FetchTodos. This listens for the FETCH_TODOS action and then calls my todos API and populates {todos: [] } =
I also have a comments section in my store todoComments. However, I would like to only populate todoComments once FETCH_TODOS has returned and populated the store.
In imperative code, this might look like:
let todos = await api.get('/todos');
await dispatch("FETCH_TODO_COMPLETE", todos)
let firstId = getState().todos[0].id
let comments = await api.get(`/todos/${firstId}/comments')
await dispatch("FETCH_COMMENTS_COMPLETE", { todo_id: firstId, comments})
The closest I saw to this was this issue in the Redux Observable Repo, but I could not understand how to do this efficiently. This is a pretty common scenario for me.
I would like to reuse as much code as possible. In this example, I may dispatch FETCH_TODOS from multiple components.
How would i accomplish this with Redux-Observable?
Based on our conversation in the comments:
In redux-observable, you can sequence things in numerous ways. You could do it all in one epic using normal RxJS, or you could split them into multiple ones. If you split them, the subsequent epic would listen for the signal that the previous one has completed its task. Something like this:
// this assumes you make your `api.get` helper return an Observable
// instead of a Promise which is highly advisable.
// If it doesn't, you could do:
// Observable.from(api.get('/url'))
// but Promises are not truly cancellable which can cause max
// concurrent connections issues
const fetchTodosEpic = action$ =>
action$.ofType('FETCH_TODOS')
.switchMap(() =>
api.get('/todos')
.map(todos => ({
type: 'FETCH_TODOS_COMPLETE',
todos
}))
);
const fetchComments = action$ =>
action$.ofType('FETCH_TODOS_COMPLETE')
.switchMap(({ todos }) =>
api.get(`/todos/${todos[0].id}/comments`)
.map(comments => ({
type: 'FETCH_COMMENTS_COMPLETE',
comments
}))
);
I'm creating an ecommerce app that uses a geolocation library (https://github.com/transistorsoft/react-native-background-geolocation).
I have an orderState:
const ordersInitState = {
lineItems: [],
status: ORDER_STATUSES.AWAITING_CHECKOUT,
};
const ordersReducer = (prevState=ordersInitState, action) => {
switch(action.type) {
...
case actions.ORDERS.REMOVE_ITEM:
const lineItems = [...prevState.lineItems];
const indexToRemove = action.payload;
lineItems.splice(indexToRemove, 1);
const status = lineItems.length > 0 ? prevState.status : ORDER_STATUSES.AWAITING_CHECKOUT;
return {
...prevState,
status,
lineItems,
};
default:
return prevState;
}
}
export default ordersReducer;
As you can see, the client is allowed to remove items from their cart. If they end up removing everything, their order status will reset. If they do end up emptying their cart (lineItems.length === 0) I want to also run a simple line from the geolocation library:
BackgroundGeolocation.removeGeofence("blah");
Where would I put this? It feels wrong to do it in the reducer because it has nothing to do with state. It also isn't specific to one particular component, so putting it in one of my components doesn't make sense.
I'm still a bit new to redux so I'm not sure where to put non-state related methods.
The often used name for what you are looking for is called "side effects" middleware. In the abstract, you want to cause an effect in an external system (in this case, the geolocation library), when the application state changes.
There are many libraries for this use case. Some of the more popular ones are redux-saga and redux-loop. They are both good tools and help give structure to managing complicated side effects, but both come with a significant conceptual overhead, and should only be used when really needed.
If you want a quick and simple solution, you can create a plain JavaScript module that subscribes to your store changes and executes the side effects for you:
import store from '../your/redux/store;
let previousCount = 0;
store.subscribe(() => {
const count = store.getState().orders.lineItems.length;
if (count === 0 && previousCount > 0) {
// someone just emptied the cart, so execute side-effect
BackgroundGeolocation.removeGeofence("blah");
}
previousCount = count;
});
And then if you find yourself needing this type of solution repeatedly, you can reach for one of the libraries mentioned above.