I am using ionic 4 and I am doing pagination using ion-infinite-scroll. My problem is I always get the duplicate page problem. Can I know how to solve this duplicate problem? Here is my code in home.page.ts:
doInfinite(event) {
this.userService.getData().then(res => {
event.target.complete();
});
}
loadData(event) {
console.log('Load more data');
this.userService.getData().then(res => {
event.target.complete();
});
}
Here is home.html
<ion-infinite-scroll (ionInfinite)="loadData($event)">
<ion-infinite-scroll-content
loadingSpinner="bubbles"
loadingText="loading ...">
</ion-infinite-scroll-content>
</ion-infinite-scroll>
It depends what your userService.getData() looks like.
It doesn't look like you are telling it to start at an offset.
Each time you pull data down, you should assign that list data to some local on-page variable, let's say dataList.
Then use this.dataList.length as the starting index for your next data request.
So some pseudo-code for how this might work would be:
let dataFeed = [];
let startAtRecord = 0;
constructor() {
this.userService.getData(startAtRecord).then(res => {
this.dataFeed = res;
this.startAtRecord = this.dataService.length;
});
}
loadData(event) {
// ask for a batch of records, starting at `startAtRecord`
this.userService.getData(startAtRecord).then(res => {
// add the new res data to the existing dataFeed
this.dataFeed = [...this.dataFeed, ...res];
// keep track of the number of records loaded
this.startAtRecord = this.dataService.length;
event.target.complete();
});
}
Do you see what I'm saying? The data service has to load the next page of data so you don't get the same one back, so it needs to track where its starting the list from.
Related
First of: I'm a beginner at Vue.js/APIs so I hope my question is not too stupid (I may not be seeing the obvious) :)
So,
Using Vue.js I'm connecting to this API and want to track the history of each crypto-currencies (no issues with getting any data from the API).
Currencies information are accessible using a URL :
https://api.coinranking.com/v2/coins
And history is accessible using another :
https://api.coinranking.com/v2/coin/ID_OF_THE_COIN/history
As you can see the second url needs the id of the specific currency which is available in the first one.
I would like to find a way to make only 1 get request for all currencies and their history rather than having to make as many requests as available currencies there are (about 50 on this API), I've tried several things but none has worked yet (for instance using the coin url and storing ids of the currencies in a table then using the history url and modifying it with the ids of the table but hit a wall) .
Here's the axios get request I have for the moment for a single currency:
const proxyurl = "https://cors-anywhere.herokuapp.com/"
const coins_url = "https://api.coinranking.com/v2/coins"
const history_url = "https://api.coinranking.com/v2/coin/Qwsogvtv82FCd/history"
//COINS DATA
axios
.get(proxyurl + coins_url, {
reqHeaders
})
.then((reponseCoins) => {
// console.log(reponseCoins.data)
this.crypto = reponseCoins.data.data.coins;
})
.catch((error) => {
console.error(error)
})
//GET ALL COINS UUIDs
axios
.get(proxyurl + coins_url, {
reqHeaders
})
.then((reponseUuid) => {
this.cryptoUuidList = reponseUuid.data.data.coins;
//access to each crypto uuid:
this.cryptoUuidList.forEach(coinUuid => {
console.log("id is: " + coinUuid.uuid)
//adding uuids to table:
this.coinsUuids.push(coinUuid.uuid);
});
})
.catch((error) => {
console.error(error)
})
// COIN HISTORY/EVOLUTION COMPARISON
axios
.get(proxyurl + history_url, {
reqHeaders
})
.then((reponseHistory) => {
//get data from last element
const history = reponseHistory.data.data.history
this.lastItem = history[history.length-1]
// console.log(this.lastItem)
this.lastEvol = this.lastItem.price
// console.log(this.lastEvol)
//get data from previous element:
this.previousItem = history[history.length-2]
this.previousEvol = this.previousItem.price
})
.catch((error) => {
console.error(error)
})
I probably forgot to give some info so let me know and will gladly share if I can
cheers,
I took a look at the API, they do not seem to give a way for you to get everything you need in one request so you will have to get each coin history separately.
However, I do se a sparkline key in the returned data, with what seems to be a few of the latest prices.
I do not know your projects's specifics but maybe you could use that for your initial screen (for example a coins list), and only fetch the full history from the API when someone clicks to see the details of a coin.
Im having issues with delete request, my post, get are working fine.
What am I doing wrong?
removeUser(id) {
axios.delete('https://jsonplaceholder.typicode.com/users' + id)
.then(function(response) {
const user = response.data;
this.users.splice(id, user);
});
if response.status === 204, then delete is succeed.
for the client, here is an axios example, notice there is a ' after users
destroy() {
return request.delete('/api/users/' + id)
}
for the server, here is an Laravel example:
if( $article->delete() ) {
return response()->json(null, 204);
} else {
abort(409);
}
I can see only 1 problem on the code you provided.
You're trying to modify the Vue instance $data users object by executing this.users.splice(id, user);. But you're inside the callback function and this no longer represents the Vue instance.
To fix this & make the users object actually modify after the response comes you'll need to do it like this :
removeUser(id) {
let that = this;
axios.delete('https://jsonplaceholder.typicode.com/users' + id)
.then(function(response) {
const user = response.data;
that.users.splice(id, user);
});
Now , I don't have any code from the back-end so I'll just make some assumptions :
The route might not be well defined > if you're using NodeJS then you should check your routes , it should look like this :
router.route('/users:id').delete(async function(req,res,next){ /* ... */ });
You might have a route problem because / is missing before the user value
1 hint : Again , if you're using NodeJS , you could use this inside your .delete route :
res.status(200).json({ errorCode : null , errorMessage : null , users : [] });
To see if you're receiving it on front-end.
I think you do need to append the trailing '/' to the URL, that way the URL is properly formed, such as "https://jsonplaceholder.typicode.com/users/123" (rather than "users123" at the end).
Aside from that, the first parameter to Array.prototype.splice is the position where item removal should begin. The second (optional) parameter, deleteCount, is the number of items to remove. Beyond deleteCount, you can pass a collection of objects which are to be inserted after the start position and after items have been removed.
You just need to find the object in your this.users array and remove it. If you want to use Array.prototype.splice for that, then you can use Array.prototype.findIndex to find the index of the user in the array then remove it:
// Find the index of the item to remove
const indexOfUserToRemove = this.users.findIndex(u => u.id === id);
// Call splice to remove the item
this.users.splice(indexOfUserToRemove, 1);
i have realtime application what i am doing get available data from backend and save as array.
when user click its going to unavailable sending index to backend its broadcast to all users who is in current page and hide unavailable data.
var vm = this;
this.$echo.channel("accept-coin").listen("AcceptCoin", response => {
vm.$set(vm.coins, response.indexid, response.coin);
vm.coins[response.indexid].result = response.result;
vm.$auth.fetchUser();
setTimeout(() => {
this.coins[response.indexid].hide = false;
}, 10000);
});
problem is if current array have 5 objects for example and 2 hide unavailable when new user open this page he will have only 3 objects
if user who have 5 objects in array if click 5th object. its working on current user but other who have 3 objects in array getting error.
what i actually want that i want to modify object with item id instead of index
simple solution i found that use findIndex methods
var vm = this;
this.$echo.channel("accept-coin").listen("AcceptCoin", response => {
var indexid = vm.coins.findIndex(f => f.id === response.coin.id); //<-- this find index with coin id so then i can do whatever
vm.$set(vm.coins, indexid, response.coin);
vm.coins[indexid].result = response.result;
vm.$auth.fetchUser();
setTimeout(() => {
this.coins.splice(indexid, 1);
}, 10000);
});
Hope this helps
I have quite a complicated situation and i'm not amazing at Vue so I need some help.
I have a Firebase DB that gets an array (clients) and displays it.
const clientsRef = db.ref('clients')
firebase: {
clients: {
source: clientsRef,
//data has been retrieved from firebase
readyCallback: function() {
this.getSiteCount() // Get number of sites associated with client
this.loaded = true // Hide loader bar once this becomes true
}
}
},
On load complete getSiteCount() will get the clients unique ID and compare it against the sites DB and count how many exist. Below code simply loops around each client and then checks how many sites have the client_id of aClient['.key']. Not really important this works and gets the count and adds it to the clients array.
getSiteCount: function() {
this.clients.forEach((server, clientIndex) => {
this.clients[clientIndex].siteCount= 0
serverContactsRef.orderByChild('client_id').equalTo(server['.key']).on('child_added', (clientDetails) => {
this.clients[clientIndex].siteCount= this.clients[clientIndex].siteCount+ 1
})
})
},
Now in my html I have v-for="clients in filterClients" and the computed function...
filterClients: function() {
function compare(a, b) {
if (a.siteCount < b.siteCount) {
return 1
}
if (a.siteCount > b.siteCount) {
return -1
}
return 0
}
return this.clients.sort(compare)
}
I suspect because the getSiteCount() function runs once the clients have been pulled (0.5s delay) from the DB it's initial siteCount value is 0 and filterClients runs before those values get set. I need to delay filterClients() until the getSiteCount() function runs or need it to update automatically when the getSiteCount() function runs.
Can someone help me make sure the initial load of the page displays the clients in order of how many sites it has (siteCount)
It was in fact a Caveat.
Vue cannot detect the following changes to an array:
When you directly set an item with the index, e.g. vm.items[indexOfItem] = newValue
I changed
this.clients[clientIndex].siteCount= 0
to
Vue.set(this.clients[clientIndex], 'contractsNr', 0)
Updates when the data comes in perfectly now.
Thanks Jacob
In one of my projects I use a dijit.Tree control. I need to add a search to the tree and show only those nodes/leafs which have the searched term in them. However I can't seem to figure out how that can be achieved. Could anybody please help me?
im not entirely sure that your question entirely but it should give hint whereas to go.
Lets use reference documentation example as offset, there is 1) a store 2) a model and 3) the tree
var store = new ItemFileReadStore({
url: "{{dataUrl}}/dijit/tests/_data/countries.json"
});
var treeModel = new ForestStoreModel({
store: store,
query: {"type": "continent"}, // note, this bit
rootId: "root",
rootLabel: "Continents",
childrenAttrs: ["children"]
});
new Tree({
model: treeModel
}, "treeOne");
Interpret the above as such; You have loaded all known countries and continents but 'user' has selected only to show continents by using query on the model - and the hierachy is then represented in a tree structure.
You want a textbox with searching capeabilities, so we hook into onChange
new dijit.form.TextBox({
onChange: function() {
...
}
});
First bit, getting variables
var searchByName = this.get("value");
var oQuery = treeModel.query;
Next, set a new query on the model - preserving the old ones with an object mixin
treeModel.query = dojo.mixin(oQuery, { name: '*'+searchByName+'*' });
Last, notify the model and its tree that changes has occurred - and requery the visible items.
treeModel._requeryTop();
NB If the top-level item (for ForestModel) is not visible, none of its child elements will show, even if the search-string matches those. (Examplewise, Alabama is not shown if US Continent is not matched by query)
EDIT
As OP has the agenda to go by the 'NB', this may not fit needs 100% but its what dojo offers with dijit.Tree.. As it will get rather a lengthy process to recode the model/store queries to include parentbranches up until root i will not do this here - but there are a few tricks still ;)
var tree = new dijit.Tree( {
/**
* Since TreeNode has a getParent() method, this abstraction could be useful
* It sets the dijit.reqistry id into the item-data, so one l8r can get parent items
* which otherwise only can be found by iterating everything in store, looking for item in the parent.children
*
*/
onLoad : function() {
this.forAllNodes(function(node) {
// TreeNode.item <-- > store.items hookup
node.item._NID = node.domNode.id
});
},
/* recursive iteration over TreeNode's
* Carefull, not to make (too many) recursive calls in the callback function..
* fun_ptr : function(TreeNode) { ... }
*/
forAllNodes : function(parentTreeNode, fun_ptr) {
parentTreeNode.getChildren().forEach(function(n) {
fun_ptr(n);
if(n.item.children) {
n.tree.forAllNodes(fun_ptr);
}
})
}
});
(non-tested, but might just work) Example:
// var 'tree' is your tree, extended with
tree.forAllNodes = function(parentTreeNode, fun_ptr) {
parentTreeNode.getChildren().forEach(function(n) {
fun_ptr(n);
if(n.item.children) {
n.tree.forAllNodes(fun_ptr);
}
})
};
// before anything, but the 'match-all' query, run this once
tree.forAllNodes(tree.rootNode, function(node) {
// TreeNode.item <-- > store.items hookup
node.item._NID = node.domNode.id
});
// hopefully, this in end contains top-level items
var branchesToShow = []
// run fetch every search (TextBox.onChange) with value in query
tree.model.store.fetch(query:{name:'Abc*'}, onComplete(function(items) {
var TreeNode = null;
dojo.forEach(items, function(item) {
TreeNode = dijit.byId(item._NID+'');
while(TreeNode.getParent()
&& typeof TreeNode.getParent().item._RI == 'undefined') {
TreeNode = TreeNode.getParent();
}
branchesToShow.push(TreeNode.item);
});
}});
// Now... If a success, try updating the model via following
tree.model.onChildrenChange(tree.model.root, branchesToShow);