I have a model - Configuration:
var Configuration = Model.extend({
props: {
name: 'string'
}
});
In the database, configuration model / table has 3 columns -> id, name and fields. The latter stores site config as a serialized array. When retrieving the entry from the database, I unserialize it and then pass it to the front end, so the front end receives this:
{
"id": 1,
"name": 'global',
"fields": {
"enabled": true,
"site_name": "Test"
}
};
What I want to do is to set whatever is inside fields object as properties on my model, or maybe session so that things get triggered throughout the site when they are updated. To visualize it, I want to achieve something like this:
var Configuration = Model.extend({
props: {
enabled: 'boolean',
site_name: 'string'
}
});
So basically, is there are a way to 'unwrap' stuff in fields object somehow?
The parse method is what you're looking for in this case. See https://github.com/AmpersandJS/ampersand-state/blob/master/ampersand-state.js#L93-L98 It allows you to transform incoming props.
Related
I have a react application that performs CRUD operations on data stored in mongodb in the cloud.mongodb.com.
The schema of the data in my react looks like this:
const restaurantSchema = new Schema({
"uuid": {
"type": "string"
},
"name": {
"type": "string"
},
"city": {
"type": "string"
}
}, {timestamps: true});
I would like to add a new field called "preference" of type number.
My questions are:
How do I add this new field of "preference"?
Can I give it a default value of say 1 when I add this new field? (There are 900 entries in the mongodb.)?
Can I give the "preference" value based on the order of the "name" field in ascending order?
thanks.
You can add and remove fields in the schema using option { strict: false }
option: strict
The strict option, (enabled by default), ensures that values passed to our model constructor that were not specified in our schema do not get saved to the db.
var thingSchema = new Schema({..}, { strict: false });
And also you can do this in update query as well
Model.findOneAndUpdate(
query, //filter
update, //data to update
{ //options
returnNewDocument: true,
new: true,
strict: false
}
)
You can check the documentation here
I might be experiencing either a bug, or I misunderstand something about general javascript syntax.
Using ServiceNow UI Builder, I'm trying to refresh the datasource of a specific data visualization component. Which requires me to use setState and send in an entire JSON blob.
The following works as expected:
api.setState('intAssignedDonut', {
"header": "Interactions assigned to one of my groups",
"datasource": [{
"isDatabaseView": false,
"allowRealTime": true,
"sourceType": "table",
"label": {
"message": "Interaction"
},
"tableOrViewName": "interaction",
"filterQuery": "active=true^assignment_groupDYNAMICd6435e965f510100a9ad2572f2b47744",
"id": "intAssigned",
"elm": {}
}],
"metric": [{
"dataSource": "intAssigned",
"id": "intAssignedMetric",
"aggregateFunction": "COUNT",
"numberFormat": {
"customFormat": false
},
"axisId": "primary"
}],
"groupBy": [{
"maxNumberOfGroups": "ALL",
"numberOfGroupsBasedOn": "NO_OF_GROUP_BASED_ON_PER_METRIC",
"showOthers": false,
"groupBy": [{
"dataSource": "intAssigned",
"groupByField": "state",
"isRange": false,
"isPaBucket": false
}]
}]
});
However, I only need to alter a few properties, not the whole thing.
So I thought I'd just clone the thing into a temp object, change what I need, then pass the cloned object back.
let clientState_intAssignedDonut = api.state.intAssignedDonut;
clientState_intAssignedDonut.header = 'Interactions assigned to one of my groups';
clientState_intAssignedDonut.datasource[0].filterQuery = 'active=true^assignment_groupDYNAMICd6435e965f510100a9ad2572f2b47744';
api.setState("intAssignedDonut", clientState_intAssignedDonut);
This seems to update the header properly, but the component doesn't refresh the datasource.
Even if I console.log api.state.intAssignedDonut it looks identical to the whole JSON blob.
EDIT: I also tried using spread operators, but I can't figure out how to target the datasource[0]
api.setState("intAssignedDonut", {
...api.state.intAssignedDonut,
header: "Interactions assigned to one of my groups",
datasource[0].filterQuery: "active=true^assignment_groupDYNAMICd6435e965f510100a9ad2572f2b47744"
});
Javascript objects are passed by reference values, and react state is immutable:
let clientState_intAssignedDonut = api.state.intAssignedDonut;
api.setState("intAssignedDonut", clientState_intAssignedDonut);
This is mutating the state directly, and React will ignore your update if the next state is equal to the previous state, which is determined by an Object.is comparison to check if both objects are of the same value, see docs
Your second attempt is heading to the right direction using spread operator:
Update method one: first copy the nested object using: JSON.parse(JSON.stringify(object)), or you can find other method in this question: What is the most efficient way to deep clone an object in JavaScript?
let copied = JSON.parse(JSON.stringify(api.state.intAssignedDonut)); // copy a nested object
copied.header = "Interactions assigned to one of my groups";
copied.datasource[0].filterQuery = "active=true^assignment_groupDYNAMICd6435e965f510100a9ad2572f2b47744";
setState("intAssignedDonut",copied);
Update method two:
setState("intAssignedDonut",{
...api.state.intAssignedDonut,
header: "Interactions assigned to one of my groups",
datasource: [{ ...state.datasource[0], filterQuery: "active=true^assignment_groupDYNAMICd6435e965f510100a9ad2572f2b47744" }]
});
Check out sandbox
I have a query that retrieves a Model. Inside this model, there are nested models with fields.
The shape is roughly like this:
{
model: [
{
id: 1,
fields: [...]
},
{
id: 2,
fields: [...]
}
]
}
Additionally, the frontend needs the model normalized into a list, like this:
{
modelFields: [
{...},
{...},
{...},
{...}
]
}
I’m attempting to derive modelFields declaratively when a query or cache update changes model. I’m trying to achieve this in type-policies section on Model: { merge: modelMergeMiddleware }, like so:
export function modelMergeMiddleware(
__: ModelFragment,
incoming: ModelFragment,
{cache, readField}: FieldFunctionOptions
) {
if (incoming) {
cache.writeQuery({
query: ModelFieldsDocument,
data: {
modelFields: incoming.fieldsets.reduce(
(fields: ModelFieldFragment[], fieldset: FieldsetFragment) => {
return fields.concat(newFields)
},
[]
)
}
})
}
return incoming
}
However, this runs into problems:
nested cache references don’t get passed through leaving empty data
readField and lodash’s _.cloneDeep both result in Readonly data that cause errors
My question is two-fold:
Is there a method to work around the problems mentioned above to derive data in a merge function?
Is there a different approach where I can declaratively derive local-only state and keep it synchronized with cached objects?
Per question 2, my backup approach is to use a reactiveVar/Recoil to store this data. This approach has the tradeoff of needing to call a setter function in all the places the Model object gets queried or mutated in the app. Not the end of the world, but it’s easy to miss a spot or forget about the setter function.
My firebase users tree has this structure:
users:
{
{
'userName': 'abc',
'userEmail' : 'abc#abc.com',
'userPreferences':
[
0:'Cinema',
1:'It'
]
},
{
'userName': 'abc',
'userEmail' : 'abc#abc.com',
'userPreferences':
[
0:'Cinema',
1:'Music'
]
}
}
Then, I try to find all users that their preference list contain 'Cinema'.
I try this code:
var ref1 = new Firebase("https://event-application.firebaseio.com/users");
$scope.user = $firebaseArray(ref1.orderByChild("userpreferences").equalTo('Cinema'));
console.log($scope.user);
But I don't get the best result. I get this record:
Your JSON structure shows preferences as userPreferences, so wouldn't the following work?
var ref1 = new Firebase("https://event-application.firebaseio.com/users");
$scope.user = $firebaseArray(ref1.orderByChild("userPreferences").equalTo('Cinema'));
console.log($scope.user);
However I think there is also another problem with your code, you're called an .equalTo('Cinema') however you're comparing it to an array, correct me if i'm wrong but I don't think the behaviour of .equalTo('Cinema') is to loop through each of the values and compare them, I think it's just a straight up comparison
If this is the case, you may need to build a custom query by reading the data from firebase and manipulating it via function available to a snapshot
In NoSQL you'll often end up with a data model that reflects the way your application uses the data. If you want to read all the users that have a preference for Cinema, you should model that in your tree:
users: {
'uid-of-abc': {
'userName': 'abc',
'userEmail' : 'abc#abc.com',
'userPreferences': [
0:'Cinema',
1:'It'
]
},
'uid-of-def': {
'userName': 'def',
'userEmail' : 'abc#abc.com',
'userPreferences': [
0:'Cinema',
1:'Music'
]
}
},
"preferences-lookup": {
"Cinema": {
"uid-of-abc": true,
"uid-of-def": true
},
"It": {
"uid-of-abc": true
},
"Music": {
"uid-of-def": true
}
}
Now you can find out what users prefer cinema with:
ref.child('preferences-lookup/Cinema').on('value', function(snapshot) {
snapshot.forEach(function(userKey) {
console.log(userKey.key()+' prefers Cinema');
});
});
This is covered in this blog post on denormalizing data with Firebase, in the Firebase documentation on structuring data and in dozens of answers here on Stack Overflow. A few:
Storing Relational "Type" or "Category" Data in Firebase Without the Need to Update Multiple Locations
Get Firebase items belonging to category
Retrieve data based on categories in Firebase
How to query firebase for property with specific value inside all children
Given is a nested model structure like this:
Model Website
+ id
+ name
+ images[] // List of Image instances
Model Image
+ imageName
+ imageUrl
A serialised version of the response looks like:
{
"id": 4711,
"name": "Some name",
"images" [
{"imageName": "Beach", "imageUrl": "http://example.com/whatever.jpg"},
...
]
}
This nested model set is persisted in a document store and is returned on request by Website.id.
There is no by-id-relation to the nested list of images, as they are persisted as a list directly in the parent model. As far as I know, the classic relations in Ext.data.Model refer to the related models via a by-id-relation.
The question is: Is there any way that I can tell the parent model to use the Image model for each of the children in it's images list?
As a first step, you can make your images data to be loaded into the model by using a field type of auto:
Ext.define('My.Model', {
extend: 'Ext.data.Model'
,fields: [
{name: 'images', type: 'auto'}
// ... other fields
}
});
Then:
myModel.get('images');
Should return:
[
{"imageName": "Beach", "imageUrl": "http://example.com/whatever.jpg"},
...
]
From there, you should theoretically be able to implement a fully automatized solution to creates the models from this data, and -- the hardest part -- try to keep these created records and the children data in the parent model synchronized. But this is a very involved hack, and a lot of entry points in Ext code base have to be covered. As an illustration, I once tried to do that for "has one" relations, and that represent a lot of code. As a result, I never took the time to consolidate this code, and finally never used it.
I would rather advocate for a simple and local (to the model) solution. You can add a simple method to your model to get the images as records. For example:
Ext.define('My.Model', {
// ...
,getImages: function() {
var store = this.imageStore;
if (!store) {
store = new Ext.data.Store({
model: 'My.ImageModel'
,data: this.get('images') || []
});
this.imageStore = store;
}
return store;
}
});
Creating a store for the associated model will save you from having to play with the proxy and the reader. It also gives you an interface that is close to Ext's default one for associations.
If you need support for loading images more than once for the same parent record, you can hook on the field's convert method.
Finally, you may also need to handle client-side modifications of associated data, in order to be able to save them to the server. If your associated model allows it, you could simply use the children store's sync method (and don't forget to update the parent model's data in the sync callback!). But if your associated model isn't connected to an endpoint on the server-side, you should be able to hook on the serialize method to save the data in the associated store (as opposed to the one stored in the parent record, that won't get updated if you work with the associated store).
Here's a last example showing both:
Ext.define('My.Model', {
extend: 'Ext.data.Model'
,fields: [
{
name: 'images'
,type: 'auto'
// enables associated data update
,convert: function(data) {
var store = this.imageStore;
if (store) {
store.loadData(data || []);
}
return data;
}
// enables saving data from the associated store
,serialize: function(value, record) {
var store = record.imageStore,
if (store) {
// care, the proxy we want is the associated model's one
var writer = store.proxy && store.proxy.writer;
if (writer) {
return Ext.Array.map(store.getRange(), function(record) {
return writer.getRecordData(record);
});
} else {
// gross implementation, simply use the records data object
return Ext.pluck(store.getRange(), 'data');
}
} else {
return record.get('images');
}
}
}
// ... other fields
}
,getImages: function() {
var store = this.imageStore;
if (!store) {
store = new Ext.data.Store({
model: 'My.ImageModel'
,data: this.get('images') || []
});
this.imageStore = store;
}
return store;
}
});
Please notice that I haven't tested this code, so it might still contains some mistakes... But I hope it will be enough to give you the general idea!