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Is there a way to override a global variable in a closure's scope?

I have an API has a signature like
on(eventName, Handler)
Where API users use it like
on('myEvent', (safeAccessObject) => {
safeAccessObject.doSomething();
});
Sometimes though, users refer to a global that I'd prefer them not to:
// assume window.dangerousAccessObject is defined
on('myEvent', (safeAccessObject) => {
dangerousAccessObject.doSomethingUnintended();
});
Is there a way to set dangerousAccessObject to null or even use some proxy of my own only within the closure of their handler?
The idea is not to create a complete and secure sandbox, but rather show helpful debug messages to the API users. In this instance both the API of on as well as dangerousAccessObject are production code that user code relies on in other contexts and so it can't be removed.

What is the way to create unit-test for sailsJS (or another framework)

Well I embraced test-driven-development in the past year while learning C# (those seem to go hand in hand). In javascript however I am struggling to find a good workflow for tdd. This is mainly due to the combination of many frameworks which seemingly consider testing a second class citizen.
As an example consider a class worker. This class would have some functionality to act upon a database. So how would I write unit tests for the functionality of this class?
In c# (and rest of C/JAVA family) I'd write this class in such a way that the constructor would take a database-connection parameter. Then during test runs the object is called with a mock-database-connection object instead of the real object. Thus no modification of the source.
In python a similar approach can be used, however apart from providing a mocking object to the constructor to handle HAS_A dependencies, we can also use dependency injection to mock IS_A dependencies.
Now apply this in javascript, and sailsJS in particular (Though a similar problem occurs with sencha and other frameworks). It seems that the code is so tightly coupled to the library/framework that I can't create manual stubs/mocks? - Other than by actually using a pre-run task to modify the source/config.js?
In sails an object (say worker, a controller) has to reside in a specific folder to work, and it "connects" automatically to the database, without me providing any notion of a database object. (Thus preventing me from actually supplying it with my own object).
Say I have a database with a table "Students", then a controller would look something like (With Students being a model defined in api/models:
const request = require('request');
module.exports = {
updateData: function (req, res) {
let idx = params.jobNumber;
Students.find({Nr:idx})
.exec(function (err, result) {
//....
});
},
};
So how would I load above function into a (mocha) test? And how would I decouple the database (used implicitly by sails) so that I can mock the functionality? - And what should I actually mock?
I of course don't wish to do integration tests, so I shouldn't build a "development database" as I don't wish to test the connection, I wish to test the controller functions.

In the documentation, they provide a nice quick example of how to set up testing using Mocha: https://sailsjs.com/documentation/concepts/testing
In the bootstrap.test.js file, all they're doing is lifting and lowering your application with Sails, just so your application has access to controllers/models/etc. within its test environment. They also show how to test individual controllers, which is essentially just making requests that hit the endpoints to fire off the controller's actions. To avoid testing the full lifecycle of a request, you can just require the controller file within a *.test.js file and test any exported action. Remember, though, Sails builds the request and response objects that get passed to the controllers. So, if you want all of the correct data and have those objects be valid, it's best to just let Sails handle it, and you only make a request to the endpoint, unless if you know exactly how to build the request and response objects. But, that's the point of a framework: you use it as intended, and test against/with it. You don't use your version of how it may work. TDD is in all languages and frameworks, you just need to fit it within your technology.
If you don't want to use a database for your test environment, you can tell it to use the sails-disk adapter by creating an environment file under config/env/ for the test environment and forcing that environment to use sails-disk.
For example...
config/env/test.js --> test environment file
module.exports = {
models: {
connection: 'localDiskDb',
migrate: 'drop',
},
port: 1337,
host: '127.0.0.1',
};
In config/connections.js the below to connections object (if not already there)...
localDiskDb: {
adapter: 'sails-disk'
},
And finally, we need to tell it to use that environment when running the tests. Modify test/bootstrap.test.js like the following...
var sails = require('sails');
before(function(done) {
// Increase the Mocha timeout so that Sails has enough time to lift.
this.timeout(10000);
// Set environment to testing
process.env.NODE_ENV = 'test';
sails.lift({
// configuration for testing purposes
}, function(err) {
if (err) {
return done(err);
}
//...
done(err, sails);
});
});
after(function(done) {
// here you can clear fixtures, etc.
// This will "refresh" the memory store so you
// have a clean test datastore every time you run tests
sails.once('hook:orm:reloaded', () => {
sails.lower((err) => {
done();
if (err) {
process.exit(1);
} else {
process.exit(0);
}
});
});
sails.emit('hook:orm:reload');
});

Adding Jason's suggestion in an "answer" format, so that others may find it more easily.
sails-mock-models allows simple mocking for sails model queries, based on sinon
Mock any of the standard query methods (ie 'find', 'count', 'update') They will be called with no side effects.
I haven't actually tried it yet (just found this question), but I'll edit this if/when I have any problems.

Sails Unit Test is perfectly explained in the following blog.
https://www.packtpub.com/books/content/how-add-unit-tests-sails-framework-application
Please refer to it.

Passing String Parameter into My Socket.io-enabled Angular 2 Component

I am in the process of moving from using http to using socket.io to bring data into to my Angular 2 app. In the example I'd like help with I am using a private version of the api.service in my component constructor. All I need to do now is call the "get" function that's defined in the api.service (already set up to use socket.io). This is what the "get" function from the api.service looks like:
public get(req: string, options: any, callback: IRequestCallback) {
// go get stuff
}
Now in my component I had been using an http get function that looked like this:
getByCategory() {
return this._http.get(this._url)
.map((response:Response) => response.json())
.catch(this._errorsHandler);
}
Now I am change this to use the socket.io function from my api.service instead. As you can see in my code at the top, the socket "get" call from the api.service is asking for 3 parameters (a string, options, and a callback). I tried this:
getByCategory() {
return this.__socket.get(this._url, this.args, function(data) {
});
}
... but now I realize the URL is already being provided in the api.service. So what's stumping me, as silly as this may sound, is what I can pass as the first parameter. I tried passing in an empty string as the first parameter, but that errored out. What string could I pass here, instead of the url? Or is there some other way around this?

First, I've had no issues with the Http module, so I'm curious why you made the switch (not that I know all of the use cases!)
That being said, it sounds like it really depends on how socket.io is handling the underlying code -- optional parameters in Typescript ("optional") normally expect undefined as a placeholder, so you could try passing undefined in this case.

Meteor: Data from External API call not rendering

I am relatively new to Meteor, and I'm trying to create a web store for my sister-in-law that takes data from her existing Etsy store and puts a custom skin on it. I've defined all of my Meteor.methods to retrieve the data, and I've proofed the data with a series of console.log statements... So, the data is there, but it won't render on the screen. Here is an example of some of the code on the server side:
Meteor.methods({
...
'getShopSections': function() {
this.unblock();
var URL = baseURL + "/sections?api_key="+apiKey;
var response = Meteor.http.get(URL).data.results;
return response;
}
...
});
This method returns an array of Object. A sample bit of JSON string from one of the returned Objects from the array:
{
active_listing_count: 20,
rank: 2,
shop_section_id: 1******0,
title: "Example Title",
user_id: 2******7
}
After fetching this data without a hitch, I was ready to make the call from the client side, and I tried and failed in several different ways before a Google search landed me at this tutorial here: https://dzone.com/articles/integrating-external-apis-your
On the client side, I have a nav.js file with the following bit of code, adapted from the above tutorial:
Template.nav.rendered = function() {
Meteor.call('getShopSections', function(err, res) {
Session.set('sections', res);
return res;
});
};
Template.nav.helpers({
category: function() {
var sections = Session.get('sections');
return sections;
}
});
And a sample call from inside my nav.html template...
<ul>
{{#each category}}
<li>{{category.title}}</li>
{{/each}}
</ul>
So, there's a few things going on here that I'm unsure of. First and foremost, the DOM is not rendering any of the category.title String despite showing the appropriate number of li placeholders. Secondly, before I followed the above tutorial, I didn't define a Session variable. Considering that the list of shop categories should remain static once the template is loaded, I didn't think it was necessary from what I understand about Session variables... but for some reason this was the difference between the template displaying a single empty <li> tag versus a number of empty <li>'s equal to category.length --- so, even though I can't comprehend why the Session variable is needed in this instance, it did bring me one perceived step closer to my goal... I have tried a number of console.log statements on the client side, and I am 100% sure the data is defined and available, but when I check the source code in my Developer Tools window, the DOM just shows a number of empty li brackets.
Can any Meteor gurus explain why 1) the DOM is not rendering any of the titles, and 2) if the Session variable indeed necessary? Please let me know if more information is needed, and I'll be very happy to provide it. Thanks!

You set the data context when you use #each, so simply use:
<li>{{title}}</li>
If a Session is the right type of reactive variable to use here or not is hard to determine without knowing what you are doing but my rough guess is that a Mini Mongo collection may be better suited for what it appears you are doing.
To get you started on deciding the correct type of reactive variable to use for this head over to the full Meteor documentation and investigate: collections, sessions, and reactive vars.
Edit: To step back and clarify a bit, a Template helper is called a reactive computation. Reactive computations inside of helpers will only execute if they are used in their respective templates AND if you use a reactive variable inside of the computation. There are multiple types of reactive variable, each with their own attributes. Your code likely didn't work at all before you used Session because you were not using a reactive variable.

Updating the client view in Meteor js after a database insertion

First off, some background
My client has a kind of a "split-view", meaning- a side-panel displaying a list of objects and a main view displaying the selected object's details. Every time the user clicks on an Object in the list, a Backbone's route is called to navigate to the id which updates a "selected" property on the Session, what causes the main view to update- pretty standard stuff.
The problem
I want the client to be as responsive as possible, therefore i'm trying to utilize Meteor's abillity to update the client immediately without waiting for a server confirmation.
My goal is that every time an Object is created, the list and the main view will be instantly updated to reflect the newly added Object. To achieve this I created a Meteor.method, create(), that uses Collection.insert and returns the id so I can use it with my Route. The method is shared across the client and server and is being called from within a template's event handler.
My first try was to store the returned id in a variable in the event handler and update the Route in the next line; For some reason, that didn't work because the method returned an undefined value. So I tried a different approach, instead of returning the id, I used it within the method to update the Route directly (if Meteor.isClient of course). That didn't work either because the id returned by Collection.insert in the client's version of the method was different from the one in the server's version.
First approach
Template.createDialog.events({
'click #btn-dialog-create': function (event, template) {
var objectId = Meteor.call('create');
appRouter.navigate("object/id/" + objectId, {trigger:true});
}
});
Second approach
Meteor.methods({
create: function () {
var ObjectId = Objects.insert({name:'test'});
if(Meteor.isClient){
appRouter.navigate("object/id/" + objectId, {trigger:true});
}
}
});
If anyone knows what's going on and can give me some directions that would be great.
Any different approaches to the problem or suggestions would be much appreciated as well.
Thanks
Update
So I tried #Pent's suggestion and I got the same result as with my second approach. For some odd reason Meteor decides to ignore my id (created with Random.id()) and inserts the object with a different one.
So I tried another approach, I used just a simple string value instead of Random.id() and voila - it worked. Riddle me that.

Answer updated:
This will be both a client and server method:
Meteor.methods({
create: function () {
var id = Random.id();
Objects.insert({_id: id, name:'test'});
if(this.isSimulation) {
appRouter.navigate("object/id/" + id, {trigger:true});
}
}
});
You can view a similar pattern from Meteor's party example: https://github.com/meteor/meteor/blob/b28c81724101f84547c6c6b9c203353f2e05fbb7/examples/parties/model.js#L56

Your problem is coused by the fact that remote methods, i.e. those which will be called on the server, don't simply return any value. Instead, they accept a callback that will be used to process the returned value (see docs). So in your first example you should probably do something like this:
Template.createDialog.events({
'click #btn-dialog-create': function (event, template) {
Meteor.call('create', function (error, result) {
if (!error)
appRouter.navigate("object/id/" + result, {trigger:true});
});
}
});
You also said:
I want the client to be as responsive as possible, therefore i'm trying to utilize Meteor's abillity to update the client immediately without waiting for a server confirmation.
I think that in this case you should definitely wait for server response. Note, that there is no chance you get the correct object id unless this is given to you by the server.
One possible way to get around this issue is to create a local (client-side) collection:
// only on client
var temporary = new Meteor.Collection(null); // null name
in which you could store your "temporary" newly created objects, and then save them to the "real" collection after the user clicks the save button. You could implement your router to respond to urls like object/new/* to get access to these objects before they're saved to your database.

The correct answer for this question is defining a client side method that's responsible for creating the unique id (preferably using Random.id() ) and calling the Meteor.methods' create(). That way, you can have the id available immediately without waiting for the server to generate one. The trick here is to generate the id outside of the Meteor.method so that the id generation happens only once for both the stub and the actual server method.
create = function(){
var id = Random.id();
Meteor.call('create', id);
return id;
}
Meteor.methods({
create: function (id) {
Objects.insert({_id: id, name:'test'});
//more code...
}
});
//and in the Template...
Template.createDialog.events({
'click #btn-dialog-create': function (event, template) {
var objectId = create();
appRouter.navigate("object/id/" + objectId, {trigger:true});
}
});