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Find duplicate object from one collection to another collection - using 2 arrays in knockout JS

In knockout JS I want to find out 1st duplicate object from my collection and return that object as modal. I have to check for 1st duplicate object from first array aginst 2nd Array based on my condition. Tried _findWhere & _.Some & _.each nothing worked. Can someone help
Here -- MyMainModal is my Moda which will have multiple objects
self.dupRecord= function (MyMainModal) {
var Modaldata= ko.mapping.toJS(MyMainModal);
return _.some(Modaldata, function (MD1) {
return _.some(Modaldata, function (MD2) {
if ((MD1.ID!== MD2.Id) &&
(MD1.Name === MD2.name));
});
});
};

How about incorporating the check for first duplicate into the mapping? Something like:
function Child(data) {
ko.mapping.fromJS(data, {}, this);
};
var model = {
children: [{
id: '1',
name: 'Billy'
}, {
id: '2',
name: 'Susy'
}]
};
var mapping = {
children: {
key: function(data) {
return ko.utils.unwrapObservable(data.id);
},
create: function(options) {
console.log('creating ' + options.data.name, options.parent);
var newChild = new Child(options.data);
if(options.parent.firstDuplicate() === undefined)
options.parent.children().forEach(function(child) {
if(child.name() === newChild.name())
options.parent.firstDuplicate([child, newChild]);
});
return newChild;
},
update: function(options) {
console.log(' updating ' + options.data.name);
return options.target;
}
}
};
var vm = {
children: ko.observableArray(),
firstDuplicate: ko.observable()
};
ko.mapping.fromJS(model, mapping, vm);
ko.applyBindings(vm);
model.children.push({
id: 3,
name: 'Billy'
});
setTimeout(function() {
console.log('--remapping--');
ko.mapping.fromJS(model, mapping, vm);
}, 2000);
I read that as, "if we're not updating the record, potentially set the first duplicate." Here's a fiddle: http://jsfiddle.net/ge1abt6a/

Detail page of split app without model

In my split app the detail view does not bind any model.
In the component.js I instantiate a named model like this:
// creation and setup of the oData model
var oConfig = {
metadataUrlParams: {},
json: true,
defaultBindingMode : "TwoWay",
defaultCountMode : "Inline",
useBatch : false
}
// ### tab-employee ###
var oModelEmpl = new sap.ui.model.odata.v2.ODataModel("/sap/opu/odata/sap/EMP_SRV"), oConfig);
oModelEmpl.attachMetadataFailed(function() {
this.getEventBus().publish("Component", "MetadataFailedEMPL");
}, this);
this.setModel(oModelEmpl, "EMPL");
The method onSelect in der master-view controller is fired by clicking on an listitem.
onSelect: function(oEvent) {
this.showDetail(oEvent.getParameter("listItem") || oEvent.getSource());
}
This will call the method showDetail
showDetail: function(oItem) {
var bReplace = jQuery.device.is.phone ? false : true;
this.getRouter().navTo("detail", {
from: "master",
entity: oItem.getBindingContext('EMPL').getPath().substr(1),
}, bReplace);
},
In the controller of the detail-view I've these two methods for updating the binding. onRouteMatched calls bindView, where I get the error-message TypeError: oView.getModel(...) is undefined.
onRouteMatched: function(oEvent) {
var oParameters = oEvent.getParameters();
jQuery.when(this.oInitialLoadFinishedDeferred).then(jQuery.proxy(function() {
var oView = this.getView();
if (oParameters.name !== "detail") {
return;
}
var sEntityPath = "/" + oParameters.arguments.entity;
this.bindView(sEntityPath);
}, this));
},
bindView: function(sEntityPath) {
var oView = this.getView();
oView.bindElement(sEntityPath);
//Check if the data is already on the client
if (!oView.getModel().getData(sEntityPath)) {
// Check that the entity specified was found.
oView.getElementBinding().attachEventOnce("dataReceived", jQuery.proxy(function() {
var oData = oView.getModel().getData(sEntityPath);
if (!oData) {
this.showEmptyView();
this.fireDetailNotFound();
} else {
this.fireDetailChanged(sEntityPath);
}
}, this));
} else {
this.fireDetailChanged(sEntityPath);
}
},
I've tried to implement this split app relative to the template generated by WebIDE. Any idea what is missing?

As you wrote yourself, you are creating a "named Model" with the name "EMPL".
In the Controller you have to use the same name to get the Model:
this.getView().getModel("EMPL");
Likewise when calling bindElement() you have to give the model name:
// Assuming sEntityPath = "/items/0"
this.getView().bindElement("EMPL>" + sEntityPath);

ES6 Classes for Data Models

I'm trying to use ES6 Classes to construct data models (from a MySQL database) in an API that I'm building. I prefer not using an ORM/ODM library, as this will be a very basic, simple API. But, I'm struggling to get my head around how to define these models.
My data entities are (these are just some simplified examples):
CUSTOMER
Data Model
id
name
groupId
status (enum of: active, suspended, closed)
Private Methods
_getState(status) {
var state = (status == 'active' ? 'good' : 'bad');
return state;
}
Requests
I want to be able to do:
findById: Providing a single customer.id, return the data for that specific customer, i.e. SELECT * FROM customers WHERE id = ?
findByGroupId: Providing a group.id, return the data for all the customers (in an array of objects), belonging to that group, i.e. SELECT * FROM customers WHERE groupId = ?
Response Payloads
For each customer object, I want to return JSON like this:
findById(1);:
[{
"id" : 1,
"name" : "John Doe",
"groupId" : 2,
"status" : "active",
"state" : "good"
}]
findByGroupId(2);:
[{
"id" : 1,
"name" : "John Doe",
"groupId" : 2,
"status" : "active",
"state" : "good"
},
{
"id" : 4,
"name" : "Pete Smith",
"groupId" : 2,
"status" : "suspended",
"state" : "bad"
}]
GROUP
Data Model
id
title
Requests
I want to be able to do:
findById: Providing a single group.id, return the data for that specific group, i.e. SELECT * FROM groups WHERE id = ?
Response Payloads
For each group object, I want to return JSON like this:
findById(2);:
{
"id" : 2,
"title" : "This is Group 2",
"customers" : [{
"id" : 1,
"name" : "John Doe",
"groupId" : 2,
"status" : "active",
"state" : "good"
},
{
"id" : 4,
"name" : "Pete Smith",
"groupId" : 2,
"status" : "suspended",
"state" : "bad"
}]
}
Requirements:
Must use ES6 Classes
Each model in its own file (e.g. customer.js) to be exported
Questions:
My main questions are:
Where would I define the data structure, including fields that require data transformation, using the private methods (e.g. _getState())
Should the findById, findByGroupId, etc by defined within the scope of the class? Or, should these by separate methods (in the same file as the class), that would instantiate the object?
How should I deal with the case where one object is a child of the other, e.g. returning the Customer objects that belongs to a Group object as an array of objects in the Group's findById?
Where should the SQL queries that will connect to the DB be defined? In the getById, getByGroupId, etc?
UPDATE!!
This is what I came up with - (would be awesome if someone could review, and comment):
CUSTOMER Model
'use strict';
class Cust {
constructor (custData) {
this.id = custData.id;
this.name = custData.name;
this.groupId = custData.groupId;
this.status = custData.status;
this.state = this._getState(custData.status);
}
_getState(status) {
let state = (status == 'active' ? 'good' : 'bad');
return state;
}
}
exports.findById = ((id) => {
return new Promise ((resolve, reject) => {
let custData = `do the MySQL query here`;
let cust = new Cust (custData);
let Group = require(appDir + process.env.PATH_API + process.env.PATH_MODELS + 'group');
Group.findById(cust.groupId).then(
(group) => {
cust.group = group;
resolve (cust)
},
(err) => {
resolve (cust);
}
);
});
});
GROUP Model
'use strict';
class Group {
constructor (groupData) {
this.id = groupData.id;
this.title = groupData.title;
}
}
exports.findById = ((id) => {
return new Promise ((resolve, reject) => {
let groupData = `do the MySQL query here`;
if (id != 2){
reject('group - no go');
};
let group = new Group (groupData);
resolve (group);
});
});
CUSTOMER Controller (where the Customer model is instantiated)
'use strict';
var Cust = require(appDir + process.env.PATH_API + process.env.PATH_MODELS + 'cust');
class CustController {
constructor () {
}
getCust (req, res) {
Cust.findById(req.params.id).then(
(cust) => {
res(cust);
},
(err) => {
res(err);
}
)
}
}
module.exports = CustController;
This seems to be working well, and I've been able to use Class, Promise and let to make it more ES6 friendly.
So, I'd like to get some input on my approach. Also, am I using the export and required features correctly in this context?

Here is another approach,
Where would I define the data structure, including fields that require data transformation, using the private methods (e.g. _getState())
You should define those fields, relationship in your model class extending the top model. Example:
class Group extends Model {
attributes() {
return {
id: {
type: 'integer',
primary: true
},
title: {
type: 'string'
}
};
}
relationships() {
return {
'Customer': {
type: 'hasMany',
foreignKey: 'groupId'
}
};
}
}
Should the findById, findByGroupId, etc by defined within the scope of the class? Or, should these by separate methods (in the same file as the class), that would instantiate the object?
Instead of having many functions use findByAttribute(attr) in Model Example:
static findByAttribute(attr) {
return new Promise((resolve, reject) => {
var query = this._convertObjectToQueriesArray(attr);
query = query.join(" and ");
let records = `SELECT * from ${this.getResourceName()} where ${query}`;
var result = this.run(records);
// Note: Only support 'equals' and 'and' operator
if (!result) {
reject('Could not found records');
} else {
var data = [];
result.forEach(function(record) {
data.push(new this(record));
});
resolve(data);
}
});
}
/**
* Convert Object of key value to sql filters
*
* #param {Object} Ex: {id:1, name: "John"}
* #return {Array of String} ['id=1', 'name=John']
*/
static _convertObjectToQueriesArray(attrs) {
var queryArray = [];
for (var key in attrs) {
queryArray.push(key + " = " + attrs[key]);
}
return queryArray;
}
/**
* Returns table name or resource name.
*
* #return {String}
*/
static getResourceName() {
if (this.resourceName) return this.resourceName();
if (this.constructor.name == "Model") {
throw new Error("Model is not initialized");
}
return this.constructor.name.toLowerCase();
}
How should I deal with the case where one object is a child of the other, e.g. returning the Customer objects that belongs to a Group object as an array of objects in the Group's findById?
In case of relationships, you should have methods like findRelations, getRelatedRecords.
var customer1 = new Customer({ id: 1, groupId: 3});
customer1.getRelatedRecords('Group');
class Model {
...
getRelatedRecords(reln) {
var targetRelationship = this.relationships()[reln];
if (!targetRelationship) {
throw new Error("No relationship found.");
}
var primaryKey = this._getPrimaryKey();
var relatedObject = eval(reln);
var attr = {};
if (targetRelationship.type == "hasOne") {
console.log(this.values);
attr[relatedObject.prototype._getPrimaryKey()] = this.values[targetRelationship.foreignKey];
} else if (targetRelationship.type == "hasMany") {
attr[targetRelationship.foreignKey] = this.values[this._getPrimaryKey()];
}
relatedObject.findByAttribute(attr).then(function(records) {
// this.values[reln] = records;
});
}
...
}
Where should the SQL queries that will connect to the DB be defined? In the getById, getByGroupId, etc?
This one is tricky, but since you want your solution to be simple put the queries inside your find methods. Ideal scenario will be to have their own QueryBuilder Class.
Check the following full code the solution is not fully functional but you get the idea. I've also added engine variable in the model which you can use to enhance fetching mechanism. All other design ideas are upto your imagination :)
FULL CODE:
var config = {
engine: 'db' // Ex: rest, db
};
class Model {
constructor(values) {
this.values = values;
this.engine = config.engine;
}
toObj() {
var data = {};
for (var key in this.values) {
if (this.values[key] instanceof Model) {
data[key] = this.values[key].toObj();
} else if (this.values[key] instanceof Array) {
data[key] = this.values[key].map(x => x.toObj());
} else {
data[key] = this.values[key];
}
}
return data;
}
static findByAttribute(attr) {
return new Promise((resolve, reject) => {
var query = this._convertObjectToQueriesArray(attr);
query = query.join(" and ");
let records = `SELECT * from ${this.getResourceName()} where ${query}`;
var result = this.run(records);
// Note: Only support 'equals' and 'and' operator
if (!result) {
reject('Could not found records');
} else {
var data = [];
result.forEach(function(record) {
data.push(new this(record));
});
resolve(data);
}
});
}
getRelatedRecords(reln) {
var targetRelationship = this.relationships()[reln];
if (!targetRelationship) {
throw new Error("No relationship found.");
}
var primaryKey = this._getPrimaryKey();
var relatedObject = eval(reln);
var attr = {};
if (targetRelationship.type == "hasOne") {
console.log(this.values);
attr[relatedObject.prototype._getPrimaryKey()] = this.values[targetRelationship.foreignKey];
} else if (targetRelationship.type == "hasMany") {
attr[targetRelationship.foreignKey] = this.values[this._getPrimaryKey()];
}
relatedObject.findByAttribute(attr).then(function(records) {
// this.values[reln] = records;
});
}
/**
* Test function to show what queries are being ran.
*/
static run(query) {
console.log(query);
return [];
}
_getPrimaryKey() {
for (var key in this.attributes()) {
if (this.attributes()[key].primary) {
return key;
}
}
}
/**
* Convert Object of key value to sql filters
*
* #param {Object} Ex: {id:1, name: "John"}
* #return {Array of String} ['id=1', 'name=John']
*/
static _convertObjectToQueriesArray(attrs) {
var queryArray = [];
for (var key in attrs) {
queryArray.push(key + " = " + attrs[key]);
}
return queryArray;
}
/**
* Returns table name or resource name.
*
* #return {String}
*/
static getResourceName() {
if (this.resourceName) return this.resourceName();
if (this.constructor.name == "Model") {
throw new Error("Model is not initialized");
}
return this.constructor.name.toLowerCase();
}
}
class Customer extends Model {
attributes() {
return {
id: {
type: 'integer',
primary: true
},
name: {
type: 'string'
},
groupId: {
type: 'integer'
},
status: {
type: 'string'
},
state: {
type: 'string'
}
};
}
relationships() {
return {
'Group': {
type: 'hasOne',
foreignKey: 'groupId'
}
};
}
}
class Group extends Model {
attributes() {
return {
id: {
type: 'integer',
primary: true
},
title: {
type: 'string'
}
};
}
relationships() {
return {
'Customer': {
type: 'hasMany',
foreignKey: 'groupId'
}
};
}
}
var cust = new Customer({
id: 1,
groupId: 3
});
cust.getRelatedRecords('Group');
var group = new Group({
id: 3,
title: "Awesome Group"
});
group.getRelatedRecords('Customer');
var groupData = new Group({
"id": 2,
"title": "This is Group 2",
"customers": [new Customer({
"id": 1,
"name": "John Doe",
"groupId": 2,
"status": "active",
"state": "good"
}),
new Customer({
"id": 4,
"name": "Pete Smith",
"groupId": 2,
"status": "suspended",
"state": "bad"
})
]
});
console.log(groupData.toObj());

Composite properties in constructor

I want to build an array of objects which look like this:
var someObject = {
id,
groupA {
propertyA: 0,
propertyB: 0,
},
groupB {
propertyA: 0,
propertyB: 0
totals {}
}
And add the following composite property:
Object.defineProperty(someObject.groupA, "propertyC",
{
get: function() {
return someObject.groupA.propertyA + someObject.groupA.propertyB;
}
});
And use the same method to add the properties:
groupB.propertyC -> groupB.propertyA + groupB.propertyB
totals.propertyA -> groupA.propertyA + groupB.propertyA
totals.propertyB -> groupA.propertyB + groupB.propertyB
totals.propertyC -> groupA.propertyC + groupB.propertyC
I got all this working by putting all this code in a function so it added someObject to an array.
But then I got to thinking that the read-only composite properties shouldn't need to be created for each object and could probably be in a prototype.
Does this make sense? And is it possible, and if so: how?

It can be done. You just need to make sure that groupA and groupB inherit from an object which has the composite property.
var proto = {};
Object.defineProperty(proto, 'propertyC', {
get : function() { return this.propertyA + this.propertyB; }
});
var someObj = {
id : '1',
groupA : Object.create(proto, {
propertyA : { value : 1 }, propertyB : { value : 2 }
}),
groupB : Object.create(proto, {
propertyA : { value : 3 }, propertyB : { value : 4 }
}),
totals : Object.create(proto, {
propertyA : { get : function() { return someObj.groupA.propertyA + someObj.groupB.propertyA; } },
propertyB : { get : function() { return someObj.groupA.propertyB + someObj.groupB.propertyB; } }
})
}
// Usage:
console.log(someObj.groupA.propertyC); // 3
console.log(someObj.groupB.propertyC); // 7
console.log(someObj.totals.propertyC); // 10

I don't know if understood well your question; but in general when you have members that you want to share across all the instances of a particular type then you should put them into the prototype of the constructor.
In your example, you're using object literal, which doesn't make it easy to do so, unless you extend the prototype of the Object constructor, which I would not recommend.
How about doing something like this:
var SomeType = function(){
this.id = 0;
this.groupA = {
propertyA: 0,
propertyB: 0
};
this.groupA = {
propertyA: 0,
propertyB: 0
};
this.total = {};
}
SomeType.prototype = {
constructor: SomeType
}
Object.defineProperty(SomeType.prototype, 'propertyC', {
get: function(){ return this.groupA.propertyA + this.groupA.propertyB }
});

Update backbone.js model with new array element

I have a backbone.js model similar to the one shown below.
Filters = Backbone.Model.extend({
defaults : {
title: [ ["title1", "easy"], ["title2", "hard"] ]
}
});
I'm trying to add an element to the first-level array, such that the model then becomes:
Filters = Backbone.Model.extend({
defaults : {
title: [ ["title1", "easy"], ["title2", "hard"], ["title3", "medium"] ]
}
});
The code I have right now is this:
function setFilters() {
var options = {};
for (var facet in facets) {
for (var facetKey in facets[facet]) {
if (!filterExists(facetKey)) {
options[facetKey] = new Array(new Array(facets[facet][facetKey], "equals"));
}
else {
(filters[facetKey]).push(new Array(facets[facet][facetKey], "equals"));
}
}
}
filters.set(options);
}
The function filterExists simply checks if the key "title" is present in the model. When I run this, it says that filters[facetKey] is undefined. But isn't this the first-level array I need to push my element into?

You can access model attributes with .get() and .set() functions, or directly via the .attributes property:
http://documentcloud.github.com/backbone/#Model-attributes
var filters = new Filters();
filters.attributes.facetKey.push( [...] );
OR
filters.set('facetKey', ( filters.get('facetKey') || []).concat([...]));
Anyway, here is your transformed function which may or may not work:
function setFilters() {
for (var facet in facets) {
for (var facetKey in facets[facet]) {
var f = [ facets[facet][facetKey], "equals" ];
if( filterExists(facetKey)) {
// OR: if( filters.attributes[ facetKey ]){
filters.attributes[ facetKey ].push( f );
}else{
filters.attributes[ facetKey ] = [ f ];
}
}
}
// trigger change event for all attributes
filters.set( filters.attributes );
}
Bonus:
(filters.attributes[ facetKey ] = filters.attributes[ facetKey ] || [] ).push(f);