I have a question that I feel should be pretty simple to answer, but I cannot find fix anywhere.
I'm querying the Uberchord website for guitar chords (documentation here)
Here is the URL I'm querying:
https://api.uberchord.com/v1/chords?nameLike=${variable}
Where variable is based on what the user types in.
The nameLike lets fuzzy match between the input and the API (For example, the url for an Fmaj7 chord is F_maj7). This works great, but it returns multiple responses. The first response is always the one I want, so I'm trying to just limit the responses to the first one that comes in. So far, I've tried adding a limit or a top filter to the URL to no avail. This is where I'm sure I'm doing something incorrect.
For limit, I've tried:
https://api.uberchord.com/v1/chords?nameLike=${fmaj7}?limit=1
and
https://api.uberchord.com/v1/chords?nameLike=${fmaj7}&limit=1
and for top I've done the same two but just replacing limit with top. The first one returns zero responses, while the second returns all responses.
Any ideas?
It isn't literally "returning multiple responses". It's just returning an array. It ALWAYS returns an array, even if there is only one element. If you only want the first element of that array, then fetch the first element of the array, just like you would with any other array. After you do the JSON decode:
chord = response[0];
Currently I have Select2 in my application, and have previously implemented ajax calls to the database to get a smaller subset based on search query entered by a user.
However, users want to be able to click the back arrow on the browser, and have the query automatically run again (something that currently does not happen with Select2). I was able to implement this by pulling the entire dataset (over 18,000 elements) in and calling select2 on that.
The problem with this is that Select2 basically does a foreach in a foreach when doing a search (foreach element in the dataset, go through each string and get the index of the query - which I understand is basically breaking the string into a char array and checking each char individually to see if the combination is found). So every time someone types a character, we're looking at over 18,000 operations, even though the majority of elements are eliminated as options.
Is there a way to make Select2 actually eliminate the options that don't match (create and bind to a temp array or something like that) or perform a binary search instead of a linear search? If not, are there any alternatives to Select2 that DO implement binary search instead of linear search, or would I need to create my own jQuery plugin to do this?
In this jsfiddle1 a hidden select element is used and a clone of that to filter input. The filtering is done with:
for (var i = 0; i < that.selector.options.length; i++) {
if (re.test(that.selector.options[i].text)) {
sclone.add(new Option(that.selector.options[i].text, i));
}
}
Where re is a RegExp created from an input field that placed above the select clone.
Maybe that's an idea to play with?
1 The language used in the first selector is dutch, but I suppose that shouldn't be obstructive to the idea.
I want to query object from Parse DB through javascript, that has only 1 of some specific relation object. How can this criteria be achieved?
So I tried something like this, the equalTo() acts as a "contains" and it's not what I'm looking for, my code so far, which doesn't work:
var query = new Parse.Query("Item");
query.equalTo("relatedItems", someItem);
query.lessThan("relatedItems", 2);
It seems Parse do not provide a easy way to do this.
Without any other fields, if you know all the items then you could do the following:
var innerQuery = new Parse.Query('Item');
innerQuery.containedIn('relatedItems', [all items except someItem]);
var query = new Parse.Query('Item');
query.equalTo('relatedItems', someItem);
query.doesNotMatchKeyInQuery('objectId', 'objectId', innerQuery);
...
Otherwise, you might need to get all records and do filtering.
Update
Because of the data type relation, there are no ways to include the relation content into the results, you need to do another query to get the relation content.
The workaround might add a itemCount column and keep it updated whenever the item relation is modified and do:
query.equalTo('relatedItems', someItem);
query.equalTo('itemCount', 1);
There are a couple of ways you could do this.
I'm working on a project now where I have cells composed of users.
I currently have an afterSave trigger that does this:
const count = await cell.relation("members").query().count();
cell.put("memberCount",count);
This works pretty well.
There are other ways that I've considered in theory, but I've not used
them yet.
The right way would be to hack the ability to use select with dot
notation to grab a virtual field called relatedItems.length in the
query, but that would probably only work for me because I use PostGres
... mongo seems to be extremely limited in its ability to do this sort
of thing, which is why I would never make a database out of blobs of
json in the first place.
You could do a similar thing with an afterFind trigger. I'm experimenting with that now. I'm not sure if it will confuse
parse to get an attribute back which does not exist in its schema, but
I'll find out, by the end of today. I have found that if I jam an artificial attribute into the objects in the trigger, they are returned
along with the other data. What I'm not sure about is whether Parse will decide that the object is dirty, or, worse, decide that I'm creating a new attribute and store it to the database ... which could be filtered out with a beforeSave trigger, but not until after the data had all been sent to the cloud.
There is also a place where i had to do several queries from several
tables, and would have ended up with a lot of redundant data. So I wrote a cloud function which did the queries, and then returned a couple of lists of objects, and a few lists of objectId strings which
served as indexes. This worked pretty well for me. And tracking the
last load time and sending it back when I needed up update my data allowed me to limit myself to objects which had changed since my last query.
Please see the following default example
http://jqueryui.com/autocomplete/ (default functionality)
When you type Scala and Schema those results are almost all the way down to the bottom although I would expect them to be first as they both start by S.
I think the reason is that it starts from the top of the list down checking to see if there are any Ss (Actionscript is the first entry in availableTags) and there is no default filtering.
If i was going to use something like cities and I limit the results to 10 and type "S" the first 10 results would not be cities that start by S but whatever contains s and is first in the list.
Is there a way around this ?
Sample fiddle here
Question2: How can the current entry get highlighted on the displayed results?
You could use the jquery plugin selectize.js.
This is how you could do it : http://plnkr.co/edit/1zmretjQGXeVnh74IMRj
As you can see by typing "sc", scala and scheme come first, and are highlighted.
I'm using Jorn Zaefferer's Autocomplete plugin on a couple of different pages. In both instances, the order of displayed strings is a little bit messed up.
Example 1: array of strings: basically they are in alphabetical order except for General Knowledge which has been pushed to the top:
General Knowledge,Art and Design,Business Studies,Citizenship,Design and Technology,English,Geography,History,ICT,Mathematics,MFL French,MFL German,MFL Spanish,Music,Physical Education,PSHE,Religious Education,Science,Something Else
Displayed strings:
General Knowledge,Geography,Art and Design,Business Studies,Citizenship,Design and Technology,English,History,ICT,Mathematics,MFL French,MFL German,MFL Spanish,Music,Physical Education,PSHE,Religious Education,Science,Something Else
Note that Geography has been pushed to be the second item, after General Knowledge. The rest are all fine.
Example 2: array of strings: as above but with Cross-curricular instead of General Knowledge.
Cross-curricular,Art and Design,Business Studies,Citizenship,Design and Technology,English,Geography,History,ICT,Mathematics,MFL French,MFL German,MFL Spanish,Music,Physical Education,PSHE,Religious Education,Science,Something Else
Displayed strings:
Cross-curricular,Citizenship,Art and Design,Business Studies,Design and Technology,English,Geography,History,ICT,Mathematics,MFL French,MFL German,MFL Spanish,Music,Physical Education,PSHE,Religious Education,Science,Something Else
Here, Citizenship has been pushed to the number 2 position.
I've experimented a little, and it seems like there's a bug saying "put things that start with the same letter as the first item after the first item and leave the rest alone". Kind of mystifying. I've tried a bit of debugging by triggering alerts inside the autocomplete plugin code but everywhere i can see, it's using the correct order. it seems to be just when its rendered out that it goes wrong.
Any ideas anyone?
max
EDIT - reply to Clint
Thanks for pointing me at the relevant bit of code btw. To make diagnosis simpler i changed the array of values to ["carrot", "apple", "cherry"], which autocomplete re-orders to ["carrot", "cherry", "apple"].
Here's the array that it generates for stMatchSets:
stMatchSets = ({'':[#1={value:"carrot", data:["carrot"], result:"carrot"}, #3={value:"apple", data:["apple"], result:"apple"}, #2={value:"cherry", data:["cherry"], result:"cherry"}], c:[#1#, #2#], a:[#3#]})
So, it's collecting the first letters together into a map, which makes sense as a first-pass matching strategy. What i'd like it to do though, is to use the given array of values, rather than the map, when it comes to populating the displayed list. I can't quite get my head around what's going on with the cache inside the guts of the code (i'm not very experienced with javascript).
SOLVED - i fixed this by hacking the javascript in the plugin.
On line 549 (or 565) we return a variable csub which is an object holding the matching data. Before it's returned, I reorder this so that the order matches the original array of value we were given, ie that we used to build the index in the first place, which i had put into another variable:
csub = csub.sort(function(a,b){ return originalData.indexOf(a.value) > originalData.indexOf(b.value); })
hacky but it works. Personally i think that this behaviour (possibly coded more cleanly) should be the default behaviour of the plugin: ie, the order of results should match the original passed array of possible values. That way the user can sort their array alphabetically if they want (which is trivial) to get the results in alphabetical order, or they can preserve their own 'custom' order.
What I did instead of your solution was to add
if (!q && data[q]){return data[q];}
just above
var csub = [];
found in line ~535.
What this does, if I understood correctly, is to fetch the cached data for when the input is empty, specified in line ~472: stMatchSets[""] = []. Assuming that the cached data for when the input is empty are the first data you provided to begin with, then its all good.
I'm not sure about this autocomplete plugin in particular, but are you sure it's not just trying to give you the best match possible? My autocomplete plugin does some heuristics and does reordering of that nature.
Which brings me to my other answer: there are a million jQuery autocomplete plugins out there. If this one doesn't satisfy you, I'm sure there is another that will.
edit:
In fact, I'm completely certain that's what it's doing. Take a look around line 474:
// loop through the array and create a lookup structure
for ( var i = 0, ol = options.data.length; i < ol; i++ ) {
/* some code */
var firstChar = value.charAt(0).toLowerCase();
// if no lookup array for this character exists, look it up now
if( !stMatchSets[firstChar] )
and so on. So, it's a feature.