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Combining multiple objects to create JSON object in Node

I am trying to construct my own JSON object from multiple online image/photography sources. The below code should explain what I am trying to accomplish:
var searchUnsplash = require('./apis/unsplash');
var searchFlickr = require('./apis/flickr');
function combineObjs(callback) {
var obj = {}
var key = 'item';
obj[key] = [];
searchFlickr.searchFlickr(searchTerm, searchCount, searchPage,
function (callback) { // each API call is in a separate file with these functions exported
obj[key].push(flickrObj); // this does not work
// console.log(flickrObj) // this works
});
searchUnsplash.searchUnsplash(searchTerm, searchCount, searchPage,
function (callback) {
obj[key].push(unsplashObj);
// console.log(unsplashObj)
});
console.log(obj)
}
combineObjs();
The goal is to end up with a JSON object like below:
["item": {
"id": 1,
"title": 2,
"content": 3,
"source": "flickr"
},
"item": {
"id": 1,
"title": 2,
"content": 3,
"source": "unsplash"
}]
etc, which I can use to power my front end.
I am a beginner to javascript and I am just working off what I have learned in tutorials and articles, so I might be using the wrong approach entirely for what I am aiming to achieve. Happy to take any pointers
search function:
function searchUnsplash(term, count, page, callback) {
request(`https://api.unsplash.com/search/photos/?per_page=${count}&page=${page}&query="${term}"&client_id=KEY&`,
function searchResult(error, response, body) {
if (!error && response.statusCode == 200) {
var info = JSON.parse(body)
for ( var i = 0; i < info.results.length; i++) {
obj = {
id: `us-${info.results[i].id}`,
}
callback(obj);
}
}
})
}
module.exports.searchUnsplash = searchUnsplash;

First, your intended result is not correct. You can't name "item" the individual array entries. A corrected and working example would be this one.
[ {
"id": 1,
"title": 2,
"content": 3,
"source": "flickr"
},
{
"id": 1,
"title": 2,
"content": 3,
"source": "unsplash"
}]
Second, you mistake JSON for your data structure. JSON is just the text notation. So, let's see first how to build a suitable data array.
let results = [];
results.push( { id:1, title:2, content:3, source:"flickr" });
results.push( { id:2, title:4, content:6, source:"unsplash" });
And then with JSON.stringify(results) will code your results into JSON.
Finally, you mix up the aynchronous calls in your code with synchronous invocations. You need to save the results on the callback of the individual functions, that is when you really obtain the responses asynchronously. Also, you need to count the pending results and invoke the final callback when all done.
So, putting all the pieces together, in a contrived fake example, we just invoke twice the search functions and so we callback when two results are combined.
function combineObjs(callback) {
let results = [];
function partialResult(obj) {
results.push(obj);
if (results.length=2) callback(results);
};
searchFlickr(searchTerm, searchCount, searchPage, partialResult);
searchUnsplash(searchTerm, searchCount, searchPage,partialResult);
}
combineObjs( function(results) { console.log(JSON.stringify(results)) });

This is excessive but it would work. It can be used over and over and over again. :D
Run the snippet to see a result
class JSONBuilder
{
constructor(contents=null)
{
if(!contents)
{
//Private objecy hash that isn't publicly accessible
var objectHash = {};
//Get stashed item
this.GetItem = function(key)
{
if(!key) throw new Error("Null or Underfined Key Passed.");
let value = objectHash[key];
if(!value) throw new Error(`Key : ${key} Not Found in JSON objectHash`);
return value;
}
//Set an item in the objecy hash
this.SetItem = function(key, value)
{
if(!key) throw new Error("Null or Underfined Key Passed.");
if(!value) throw new Error("Null or Underfined Key Not Found.");
objectHash[key] = value;
}
//Remove item from the hash
this.DeleteItem = function(key)
{
if(!key) throw new Error("Null or Underfined Key Passed.");
if(!objectHash[key]) throw new Error(`Key : ${key} Not Found in JSON objectHash`);
objectHash.DeleteItem(key);
}
//Turn items into a JSON object
this.Build = function()
{
return JSON.stringify(objectHash);
}
}
else
{
//If a string is passed as a paremeter, reconstruct from that
try
{
objectHash = JSON.parse(contents);
}
catch(Err)
{
console.log("Parsing of JSON Content Failed.");
throw Err;
}
}
}
}
class Item
{
constructor(id, source, content, title)
{
this.Id = id;
this.Source = source;
this.Content = content;
this.Title = title;
}
}
let builder = new JSONBuilder();
let itemContainer = [];
itemContainer.push(new Item(1, 'flicker', 'stuff', 'item1'));
itemContainer.push(new Item(2, 'flicker', 'morestuff', 'item2'));
builder.SetItem('items', itemContainer);
console.log(builder.Build());

An intelligent way of calling a variable length number of JavaScript methods in a web page

I have created a new web app that has 10 pages / forms and during the load of those pages 6 of the pages / forms call the same JavaScript methods and 4 call the same plus some additional methods. I can obviously call the the methods individually in the page but I'm wondering how I can do this in a more intelligent manner.
Currently all I'm doing is calling the methods at the bottom of the page like:
<script>
somemethod1(someparam1);
somemethod2(someparam1, someparam2);
somemethod3();
somemethod4();
somemethod5(someparam1);
</script>
It would be nicer to call something like:
<script>
Execute('somemethod1', 'somemethod2''somemethod3', 'somemethod4', 'somemethod5')();
</script>

I don't think its a good practice to do it. But sure, it'd be nicer to have Execute function like that if you don't need to pass any parameters.
You can do it like,
function test1() {
console.log('test1');
}
function test2() {
console.log('test2');
}
var Execute = function() {
for (var i = 0; i < arguments.length; i++) {
var funcName = arguments[i];
if (typeof window[funcName] == 'function') {
window[funcName]();
}
}
}
Execute('test1', 'test2')
However, as your question edited that you need to pass specific parameter/s to one or more of the functions, here's the intelligent way to do it.
test1(param1);
test2(param2, param1);

If you have uniform procedures and you need to call them in a certain order, like my example below for iteration nested arrays, then you could use the given proposal, which uses the following functions for the function before.
This might not work for other needs.
function Callback(array) {
this.array = array;
}
Object.defineProperties(Callback.prototype, {
start: {
get: function () {
return this.getCallback(0);
}
},
getCallback: {
value: function (i) {
var that = this;
return this.array[i].bind({ get next() { return that.getCallback(i + 1); } });
}
}
});
// example
function getSubmodel(model, submodel) {
var callback = new Callback([
function (a) { a.Categories.forEach(this.next); },
function (a) { a.forEach(this.next); },
function (a) { if (a.brandname === model) { a.models.forEach(this.next); } },
function (a) { if (a.name === submodel) { a.submodel.forEach(this.next); } },
function (a) { result.push(a.name); }
]),
result = [];
data.forEach(callback.start);
return result;
}
var data = [{
Storename: "Zig Zag Mobiles",
Shopid: "asdef1234",
Categories: [[{
models: [{
submodel: [{
price: null,
name: "Lumia 735 TS"
}, {
price: "3200",
name: "Lumia 510"
}], name: "Lumia"
}],
brandname: "Nokia",
}]]
}];
console.log(getSubmodel('Nokia', 'Lumia'));
.as-console-wrapper { max-height: 100% !important; top: 0; }

it would be nicer to call something like Execute('somemethod1',
'somemethod2''somemethod3', 'somemethod4', 'somemethod5')();
Provided that you do not need to pass in argument(s) to the individual method you can do this:
[func1, func2, func3].map(function(func){
func();
});
Otherwise the way to do it is to just call the methods with the required arguments as you are already doing now unless there is really significant benefits to be gained from creating an abstraction where you can pass in both the method to be called and its associated arguments.

Testing RxJS using TestScheduler with Promises and angular

I'm having a small issue using RxJS and Angular (not Angular 2) that I'm sure indicates I'm just doing something wrong, but I'm not sure exactly what.
I have a function that creates an rx.Observable stream that I would like to test. A simplified version of the function is below:
ResourceCollection.prototype.rxFetch = function() {
var scheduler = this.injectedScheduler;
var result = functionThatReturnsAnObservable(theseParams).concatMap(function(items) {
var promises = _.map(readFromExternal(items), function(promise) {
// results of this promise should be ignored
return Rx.Observable.fromPromise(promise, scheduler);
});
promises = promises.concat(_.map(items, function(item) {
// callEvent returns EventResult, these values should be passed on
return Rx.Observable.fromPromise(callEvent(item), scheduler);
}));
return promises;
}).concatMap(function(x) { return x; }).filter(function(res) {
return (res instanceOf EventResult);
}).toArray();
return result;
});
My test function looks like this:
describe('query', function() {
var customers;
var scheduler;
beforeEach(function() {
scheduler = new Rx.TestScheduler();
customers = new ResourceCollection({
url: '/api/customers',
keyName: 'CustomerId',
globalActions: {
rxQuery: { method: 'GET', isArray: true }
}
});
$httpBackend.whenGET('/api/customers/rxQuery').
respond(function() {
return [200, [
{ CustomerId: 1, Name: 'Brian', Region: 'North' },
{ CustomerId: 2, Name: 'Ravi', Region: 'East' },
{ CustomerId: 3, Name: 'Ritch', Region: 'East' },
{ CustomerId: 4, Name: 'Jeff', Region: 'West' },
{ CustomerId: 5, Name: 'Brandon', Region: 'West' }
]];
});
});
it('rxFetch customers', function(done) {
var vals;
customers.injectedScheduler = scheduler
var result = customers.rxFetch();
result.subscribe(function(values) {
vals = values;
});
$httpBackend.flush();
// my question is here - what can I do to get rid of this loop?
while (vals == null) {
scheduler.advanceBy(100);
$rootScope.$apply();
}
scheduler.start();
expect(vals.length).toEqual(5);
expect(vals[0]).toBe(customers[0]);
done();
});
});
The issue is a simple one - while the while loop in the test is in there, the test will produce the correct results (which is an array that contains the results of all the callEvent functions). Replace the while loop with a scheduler.scheduleAbsolute (or some other such call) combined with a $rootScope.$apply, and only one of the promises from the callEvent function will complete. Call it twice, and two of them will complete, etc (hence the while loop).
But the while loop is pretty ugly - and I'm sure there has to be an cleaner way to get this test to pass. Many thanks to anyone who can point me in the correct direction.

How can I unit test a complex promise chain?

I have some JavaScript code:
var findLeastUsedPassage;
findLeastUsedPassage = function(StudentId) {
var passageCounts;
passageCounts = [];
return db.Passage.findAll({
where: {
active: true
}
}).each(function(dbPassage) {
var passage;
passage = dbPassage.get();
passage.count = 0;
return passageCounts.push(passage);
}).then(function() {
return db.Workbook.findAll({
where: {
SubjectId: 1,
gradedAt: {
$ne: null
},
StudentId: StudentId
},
include: [
{
model: db.WorkbookQuestion,
include: [db.Question]
}
],
limit: 10,
order: [['gradedAt', 'DESC']]
});
}).each(function(dbWorkbook) {
return Promise.resolve(dbWorkbook.WorkbookQuestions).each(function(dbWorkbookQuestion) {
var passageIndex;
passageIndex = _.findIndex(passageCounts, function(passageCount) {
return passageCount.id === dbWorkbookQuestion.Question.PassageId;
});
if (passageIndex !== -1) {
return passageCounts[passageIndex].count++;
}
});
}).then(function() {
passageCounts = _.sortBy(passageCounts, 'count');
return passageCounts;
});
};
and I want to unit test it (I think). I instrumented mocha to do the testing, but my test doesn't seem all that.. thorough:
describe('Finding the least used Passage', function() {
it('should have a function called findLeastUsedPassage', function() {
return expect(WorkbookLib.findLeastUsedPassage).to.exist;
});
return it('should return the least used passages for a student', function() {
return WorkbookLib.findLeastUsedPassage(10).then(function(passageCounts) {
var passageCountsLength;
passageCountsLength = passageCounts.length;
expect(passageCountsLength).to.equal(74);
expect(passageCounts[0].count).to.be.at.most(passageCounts[1].count);
expect(passageCounts[1].count).to.be.at.most(passageCounts[5].count);
expect(passageCounts[56].count).to.be.at.most(passageCounts[70].count);
return expect(passageCounts[70].count).to.be.at.most(passageCounts[73].count);
});
});
});
What's the right approach to unit testing something like this?

This is a great resource for understanding how to break up your code to able to test it.
Currently, you're code can't be tested well because the logic is all intermingled between multiple database calls, business logic, and glue code. What you need to do is break it all out into multiple named functions that each do one thing, like you do now. Expect that instead of creating the functions in the chain you should create them outside of the chain, then just call them in the promise chain.
var passageCounts = [];
function findAllActivePassages() {
passageCounts = [];
return db.Passage.findAll({
where: {
active: true
}
})
}
function countPassages(dbPassage) {
var passage;
passage = dbPassage.get();
passage.count = 0;
return passageCounts.push(passage);
}
function findAllSubjects(StudentId) {
return db.Workbook.findAll({
where: {
SubjectId: 1,
gradedAt: {
$ne: null
},
StudentId: StudentId
},
include: [
{
model: db.WorkbookQuestion,
include: [db.Question]
}
],
limit: 10,
order: [['gradedAt', 'DESC']]
});
})
// ...
findAllActivePassages()
.each(countPassages)
.then(function() {
return findAllSubjects(studentId)
})
// ...
Now you can test each function individually and in isolation to ensure that they do what you expect

So for starters, you probably want to break up your promise chains to make the discrete units of your code more apparent. I did some quick psuedo javascript (most familliar w/ node so apologies if this doesn't fit vanilla javascript as cleanly).
var p1 = db.Passage.findAll({ where: { active: true }})
var p2 = db.Workbook.findAll({
where: {
SubjectId: 1,
gradedAt: {
$ne: null
},
StudentId: StudentId
},
include: [
{
model: db.WorkbookQuestion,
include: [db.Question]
}
],
limit: 10,
order: [['gradedAt', 'DESC']]
});
Promise.all([p1, p2])
.then(function(results){
var passages = results[0]
var workbooks = results[1];
var passageCounts = {};
passages.foreach(function(passage){
passagecounts[passage.get().id] = 0
});
workbooks.foreach(function(workbook){
workbook.workBookQuestions.foreach(function(question){
return passageCounts[dbWorkbookQuestion.Question.PassageId] += 1;
})
});
return Promise.resolve(passageCounts)
}).then(function(passageCounts){
passageCounts = _.sortBy(passageCounts, 'count'); //this has to change but don't know what underscore offers for sorting an object used as a hashmap
return passageCounts;
});
Now as far as unit testing - you're looking to test discrete units of it so the following use cases seem reasonable:
Do I get any result back when expected?
If i give it specific values are they sorted in the way I expect?
If I have no results for either query does it break? Should it?
It may behoove you to break out the DB calls from the logic and pass the results into a method, makes testing some of the scenarios a bit easier.

why [Circular] is getting added in the hash

here is my code
db.query(str, arr, function selectCb(error, results, fields) {
if (error) {
return proceed(false, {errno:'010',message:error.message}, request);
}
var q = async.queue(function (results, callback) {
// add the gib infor
if (results.refertype=='G') {
var input={};
input.fields="*";
input.gibname=results.refername;
gib.getgibinternal(input, makeCallback(i));
function makeCallback(index) {
return function(gresult) {
results.gib=gresult.data[0];
callback(results);
}
}
// add the user info
} else if(results.refertype=='U') {
var input={};
input.username=results.refername;
input.fields="*";
user.getuserinternal(input, makeCallbackuser(i));
function makeCallbackuser(index) {
return function(gresult) {
results.user=gresult.data[0];
callback(results);
}
}
}
}, results.length);
// assign a callback
q.drain = function() {
return proceed(true, self.results, self.request);
}
self.results=results;
for (var i=0; i<results.length; i++) {
// the first console
console.log(results[i]);
// add some items to the queue
q.push(results[i], function (results) {
results[i]=results;
self.results[i]=results;
//the second console.
console.log(results);
});
}
if (results.length==0) {
return proceed(true, results, request);
}
});
The out put of above code is :
// the first console
{ cardid: 30,
cardtype: 'I',
status: 'A',
refername: 'admin',
refertype: 'U' }
// the second console
{ '1': [Circular],
cardid: 30,
cardtype: 'I',
status: 'A',
refername: 'admin',
refertype: 'U',
user:
{ name: 'admin',
username: 'admin',
deleted: 'N' } }
how this '1': [Circular], get added .?

This bit:
q.push(results[i], function (results) {
is the same as this (with some renaming to make it easier to track the scope):
q.push(self.results[i], function(r) {
r[i] = r; // <------------------- Look at me!
self.results[i] = r;
//the second console.
console.log(r);
});
The self.results[i] change just comes from the self.results=results; right above your for loop. The interesting part is this:
r[i] = r;
If i is 1 you will have added a property named 1 to r whose value is r itself, hence the [Circular]. I would hazard a guess that results.length is 2 and that your function is acting as a closure over i and ending up with using the last value that i had and that's why you get the '1' rather than a '0' property.
I see three main Things that could be causing you trouble:
The classic closure problem with i.
Too many things were called results so it was easy to lose track of which one you were working with.
The circular reference: r[i] = r;.
Another possible source of confusion is that results and self.results are the same object but that might be okay.

Seems like it's a circular reference and console.log is muffling it. Try doing console.log(Object.keys(results['1'])); for more information on what's inside the Object 1