I have a collection which I am sorting using and sortByDesc('created_at'). When I dd() it before returning to my view, it changes the order.
However, as soon as I pass it to my vue component, it changes the order back.
Why is this happening? Is there a way of solving this?
I keep forgetting about this all the fonking time, but it's usually because the collection-sorting methods retain their keys. Quoting the docs (https://laravel.com/docs/5.6/collections#method-sortby):
The sortBy method sorts the collection by the given key. The sorted collection keeps the original array keys, so in this example we'll use the values method to reset the keys to consecutively numbered indexes:
Related
Following the tutorial by Dan Abramov here: https://egghead.io/lessons/javascript-redux-normalizing-the-state-shape
He doesn't seem to explain the benefit of maintaining an extra reducer with an array of todo IDs (allIds), would it not be easier to have just the one byId reducer and user Object.keys or Object.values to iterate over it?
The sample Todo app shows a list of todos, in the order in which they were created. It's not possible to retrieve that ordered list in a way that is guaranteed to work across browsers using an Object and Object.keys.
JS Object properties are unordered, but arrays have an order. So the ordering of the output of Object.keys() is not guaranteed to have any relationship to the order in which the keys were added. The array allows the reducer to display the todos in the order in which they were added.
Theoretically you could use a Map, as the keys in a Map are ordered. However, there's no way to re-order the contents of a Map. With an array you could re-order the IDs without needing to touch the todo objects themselves.
In other words, the array data structure is better suited to storing ordered lists than both Object and Map.
I have a rest-api that returns a list of users when called. The API uses the org.springframework.data.domain.Pageable to paginate and sort the results. This works by simply passing the pageable to the JPA repository, which then returns the desired page.
For some reason, when sorting by the first name, there is a chance that a duplicate entry will appear, but only if multiple entries have the same first name. However, this never happens when sorting by lastName. Both are simply strings in the entity, there is no discernable difference besides the property name.
Have any of you ever encountered this and if so, how did you fix it?
EDIT: To clarify, there is basically no logic of mine between the controller and the repository. I just pass the pageable through and return the results.
EDIT 2: Solved! Interesting titbit: The reason why the issue was only occurring when sorting by the first name was that only there were there always records that appeared on page 1 and 2, regardless which way the entries were sorted. Lucky me that our testers used that specific test data, or I might have never noticed.
Yes, I have seen that: a record can appear on, say, page 1 and then again on page 2.
This is an issue at the database level. For example 10 items per page and items at positions 10 and 11 have the same value for the property then it can be random which one appears in which position in each resultset.
Therefore apply a secondary sort on a unique property - the database ID for example - in order to ensure consistent ordering across requests.
I am new to handsontable.
My handsontable rows are readonly.
I wanted to remove all rows of handsontable on a button click.
Please help me.
Do update with empty dataset:
handsontableInstance.updateSettings({
data : []
});
This removes all rows (and leave header if there is some).
There are many ways to "remove" all rows. For example, one, and the easiest, would be to empty your data array. So say that you initialized your HOT instance with the data field as array dataArray. Your button would only need do:
$("#buttonId").click(function() { dataArray = [];})
That would be the easiest way but of course you'd be bypassing HOT. This means that if your application gets more complex and you rely on handlers such as afterRemoveRow, then this method will bypass them. In this latter case, you'd want to use the hot.alter() method as follows:
hot.alter('remove_row', 0); // would remove the row at index 0;
With this I am assuming you know how to use a for loop that could iterate through all rows and remove them, one by one. An expensive operation but it would ensure all the proper handlers get called.
tableInstance.clear()
Clears the data from the table (the table settings remain intact).
refer to the
doc
I have an map function in a view in CouchDB that emits non-unique two array keys, for documents of type message, e.g.
The first position in the array key is a user_id, the second position represents whether or not the user has read the message.
This works nicely in that I can set include_docs=true and retrieve the actual documents. However, I'm retrieving duplicate documents in that case, as you can see above in the view results. I need to be able to write a view that can be queried to return unique messages that have been read by a given user. Additionally, I need to be able to efficiently paginate the resultset.
notice in the image above that [66, true] is emitted twice for doc id 26a9a271de3aac494d37b17334aaf7f3. As far as I can tell, with the keys in my map function, I cannot reduce in such a way that unique documents will be returned.
the next idea I had was to emit doc._id also in the map function and reduce with group_level=exact the result being:
now I am able to get unique document ids, but I cannot get the documents without doing a second query. And even in the case of a second query, it will require a lot of complexity to do pagination like this (at least I think so).
the last idea I came up with is to emit the entire document rather than the doc._id in the third position in the array key, then I can access the entire document and likely paginate. This seems really brutish.
So my question is:
Is #3 above a terrible idea? Is there something I'm missing? Is there a better approach?
Thanks in advance.
See #WickedGrey's comment to the question. The solution is to ensure that I never emit the same key twice for one document. I do this in the map function by keeping track of the keys as I emit them in an array, then skipping the emit if the key exists in the array.
I need to keep the datastore sorted. When I add sortInfo datastore gets sorted for the first time. When I add another item it goes as last element. Therefore datastore is not in sorted order.
Even if i change the value of the cell in column that needs to be sorted also the order gets disturbed.
How to keep the datastore in dojo be sorted?
You'd need to call a save() on the store to commit your changes for your sort order to be reflected.