How to create Backbone collection from following json array? - javascript

I am getting a following JSON(/users.json) which contains users:
[
[
{ "id": "43343", "project_id": "1", "username": "Amy" }
{ "id": "34244", "project_id": "1", "username": "Tommy" }
],
[
{ "id": "76575", "project_id": "2", "username": "Izzy" }
{ "id": "13322", "project_id": "2", "username": "Sam" }
],
{ "id": "09983", "project_id": "3", "username": "Max" }
]
When project has one user I get one user hash which is not in array.
I would like to build a Backbone collection with all users. How to do that?

You provide an array of arrays of users. So to fetch all users in the init method, you can give it data but as an array of users, i.e. you will flatten this original array of arrays once with underscore flatten method :
data = _(data).flatten(true);
Then the collection constructor will natively understand your json array.
But maybe you already do this transformation in the fetching method and this is not the problem you are facing..

If you have defined a collection (say userCollection) with a user model you should be able to simply do something like this:
var col;
$.getJSON("/users.json", function(data) {
col = new userCollection(data);
});
This would more likely be done in the fetch function of the collection, but the principle here is that you can pass an array of objects to a collection and it will marshal all from json to backbone models.

Related

DocumentDB: How to filter document on array within array?

Let's say I have the following document:
{
"Id": "1",
"Properties": [
{
"Name": "Name1",
"PropertyTypes": [
"Type1"
]
},
{
"Name": "Name2",
"PropertyTypes": [
"Type1",
"Type2",
"Type3"
]
}
]
}
When I use the following SQL:
SELECT c.Id FROM c
JOIN p in c.Properties
WHERE ARRAY_CONTAINS(p.PropertyTypes,"Type1")
I get as return:
[
{
"Id": "1"
},
{
"Id": "1"
}
]
How do I change my query so that it only returns distinct documents?
As far as I know, Distinct hasn't supported by Azure Cosmos DB yet.
It seems that there is no way to remove the repeat data in the query SQL level.
You could handle with your query result set in the loop locally.
However, if your result data is large,I suggest you using a stored procedure to handle with result data in Azure Cosmos DB to release the pressure on your local server.
You could refer to the official tutorial about SP.

JSON list optimization

I want to create a JSON API that returns a list of objects. Each object has an id, a name and some other information. API is consumed using JavaScript.
The natural options for my JSON output seems to be:
"myList": [
{
"id": 1,
"name": "object1",
"details": {}
},
{
"id": 2,
"name": "object2",
"details": {}
},
{
"id": 3,
"name": "object3",
"details": {}
},
]
Now let's imagine that I use my API to get all the objects but want to first do something with id2 then something else with id1 and id3.
Then I may be interested to be able to directly get the object for a specific id:
"myList": {
"1": {
"name": "object1",
"details": {}
},
"2": {
"name": "object2",
"details": {}
},
"3": {
"name": "object3",
"details": {}
},
}
This second option may be less natural when somewhere else in the code I want to simply loop through all the elements.
Is there a good practice for these use cases when the API is used for both looping through all elements and sometime using specific elements only (without doing a dedicated call for each element)?
In your example you've changed the ID value from 1 to id1. This would make operating on the data a bit annoying, because you have to add and remove id all the time.
If you didn't do that, and you were relying on the sorted order of the object, you may be in for a surprise, depending on JS engine:
var source = JSON.stringify({z: "first", a: "second", 0: "third"});
var parsed = JSON.parse(source);
console.log(Object.keys(parsed));
// ["0", "z", "a"]
My experience is to work with arrays on the transport layer and index the data (i.e. convert array to map) when required.

Indexing array values in an object in an IndexedDB

For a Chrome app, wich stores data in IndexedDB, i have a object like this:
var simplifiedOrderObject = {
"ordernumber": "123-12345-234",
"name": "Mr. Sample",
"address": "Foostreet 12, 12345 Bar York",
"orderitems": [
{
"item": "brush",
"price": "2.00"
},
{
"item": "phone",
"price": "30.90"
}
],
"parcels": [
{
"service": "DHL",
"track": "12345"
},
{
"service": "UPS",
"track": "3254231514"
}
]
}
If i store the hole object in an objectStore, can i use an index for "track", which can be contained multiple times in each order object?
Or is it needed or possibly better/faster to split each object into multiple objectStores like know from relational DBs:
order
orderitem
parcel
The solution should also work in a fast way with 100.000 or more objects stored.
Answering my own question: I have made some tests now. It looks like it is not possible to do this with that object in only 1 objectStore.
An other example object which would work:
var myObject = {
"ordernumber": "123-12345-234",
"name": "Mr. Sample",
"shipping": {"method": "letter",
"company": "Deutsche Post AG" }
}
Creating an index will be done by:
objectStore.createIndex(objectIndexName, objectKeypath, optionalObjectParameters);
With setting objectKeypath it is possible to address a value in the main object like "name":
objectStore.createIndex("name", "name", {unique: false});
It would also be possible to address a value form a subobject of an object like "shipping.method":
objectStore.createIndex("shipping", "shipping.method", {unique: false});
BUT it is not possible to address values like the ones of "track", which are contained in objects, stored in an array. Even something like "parcels[0].track" to get the first value as index does not work.
Anyhow, it would be possible to index all simple elements of an array (but not objects).
So the following more simple structure would allow to create an index entry for each parcelnumber in the array "trackingNumbers":
var simplifiedOrderObject = {
"ordernumber": "123-12345-234",
"name": "Mr. Sample",
"address": "Foostreet 12, 12345 Bar York",
"orderitems": [
{
"item": "brush",
"price": "2.00"
},
{
"item": "phone",
"price": "30.90"
}
],
"trackingNumbers": ["12345", "3254231514"]
}
when creating the index with multiEntry set to true:
objectStore.createIndex("tracking", "trackingNumbers", {unique: false, multiEntry: true});
Anyhow, the missing of the possibility to index object values in arrays, makes using indexedDB really unneeded complicated. It's a failure in design. This forces the developer to do things like in relational DBs, while lacking all the possibilities of SQL. Really bad :(

sails.js update or add new row

I'm starting a project using sails.js and I'ma bit confused about something.
I have a structure like this
[
{
"logins": {
"1": {
"login time": "2016-04-02T11:40:06.731Z"
}
}
"username": "test",
"password": "test",
"createdAt": "2016-04-02T11:40:06.731Z",
"updatedAt": "2016-04-02T11:40:06.731Z",
"id": "56ffaf9692bcf108169ef7c8"
}
]
now when a user logs in again, ideally I want the data to look like this
[
{
"logins": {
"1": {
"login time": "2016-04-01T11:40:06.731Z"
},
"2": {
"login time": "2016-04-02T11:40:06.731Z"
}
}
"username": "test",
"password": "test",
"createdAt": "2016-04-01T11:40:06.731Z",
"updatedAt": "2016-04-01T11:40:06.731Z",
"id": "56ffaf9692bcf108169ef7c8"
}
]
However, I cannot for the live of me figure out how to "update" or "insert" a new row under "logins" for my user.
Creating the first record is fine and so far the best I could come up with is reading the current value for logins into a buffer and then re-inserting all the values.
That seems clumsy. Does anyone know if sails has some built in method to support what I'm trying to achieve?
I would change your 'Logins' argument to array. Than you can use $push while updating. Waterline support only $set operation, so if you want to do that you need to use .native() like that:
Model.native(function(error,collection){
collection.update(
{_id:YOURID}, // where condition
{$push:{logins:new Date()}}, // push new value to array
{}, // options
function(error,result){} // callback
)
})
To see what you can do with native, see Node.js MongoDB Driver API - Collections

Ember.js REST adapter handling different JSON structure

I'm using REST adapter, when I call App.Message.find() Ember.js makes call to the /messages to retrieve all messages and expect to see JSON structure like this:
{
"messages": [] // array contains objects
}
However API I have to work with response always with:
{
"data": [] // array contains objects
}
I only found the way1 to change namespace or URL for the API. How to tell REST adapter to look for data instead of messages property?
If this is not possible how to solve this problem? CTO said we can adapt API to use with REST adapter as we want, but from some reason we can't change this data property which will be on each response.
Assuming you are ok with writing your own adapter to deal with the difference, in the success callback you can simply modify the incoming name from "data" to your specific entity -in the case above "messages"
I do something like this to give you and idea of what if possible in a custom adapter
In the link below I highlighted the return line from my findMany
The json coming back from my REST api looks like
[
{
"id": 1,
"score": 2,
"feedback": "abc",
"session": 1
},
{
"id": 2,
"score": 4,
"feedback": "def",
"session": 1
}
]
I need to transform this before ember-data gets it to look like this
{
"sessions": [
{
"id": 1,
"score": 2,
"feedback": "abc",
"session": 1
},
{
"id": 2,
"score": 4,
"feedback": "def",
"session": 1
}
]
}
https://github.com/toranb/ember-data-django-rest-adapter/blob/master/packages/ember-data-django-rest-adapter/lib/adapter.js#L56-57
findMany: function(store, type, ids, parent) {
var json = {}
, adapter = this
, root = this.rootForType(type)
, plural = this.pluralize(root)
, ids = this.serializeIds(ids)
, url = this.buildFindManyUrlWithParent(store, type, ids, parent);
return this.ajax(url, "GET", {
data: {ids: ids}
}).then(function(pre_json) {
json[plural] = pre_json; //change the JSON before ember-data gets it
adapter.didFindMany(store, type, json);
}).then(null, rejectionHandler);
},

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