I'm using Parse's Cloud Code to write a method that will return and array containing two sub arrays. With on array being an array of teams and the other being an array containing arrays of those team members. With the purpose of getting a list of teams and their team members. The arrays will be passed to an iOS front end to display.
My data is currently structured so that there is a Team object that can have multiple Users but a User can only have one team.
Here's my cloud function as it lives now:
var arrayOfUsers = [];
var arrayOfTeamMembers = [];
var arrayOfTeams = [];
Parse.Cloud.define("GetTopTeams", function(request, response) {
var query = new Parse.Query("Teams");
arrayOfTeams = [];
arrayOfTeamMembers = [];
fullArray = [];
query.find().then(function(teams) {
//returns a raw list of teams
return teams;
}).then(function(teams) {
arrayOfUsers = [];
teams.forEach(function(team) {
//add team to subArray1
arrayOfTeams.push(team);
//searches for all users within the team
var memberQuery = new Parse.Query(Parse.User);
memberQuery.equalTo('team', team);
memberQuery.find().then(function(tMember) {
//adds the team member to initial array
arrayOfUsers.push(tMember);
});
}).then(function(){
//pushes the finished array to the team member array
return arrayOfTeamMembers.push(arrayOfUsers);
}).then(function() {
return arrayOfTeams;
});
}).then(function() {
return response.success([arrayOfTeams, arrayOfTeamMembers]);
});
});
I'm able to populate the arrayOfTeams but getting the arrayOfTeamMembers is proving to be difficult. Is there a better way to nest them? I tried promises but am unfamiliar with Javascript promises. I've found similar posts but none that address the issue I'm having. Any suggestions?
You could use Underscore. It is already available in Cloud Code. Using it you will need only one query. And you could write something like this:
var memberQuery = new Parse.Query(Parse.User);
memberQuery.exists("team");
memberQuery.include("team");
memberQuery.find().done(function(users){
var usersGroupedByTeam = _.groupBy(users, function(user) {
return user.get("team").id;
});
var arrayOfTeams = _.chain(users)
.map(function(user) { return user.get("team"); })
.uniq(function(team) { return team.id; })
.value();
response.success({
arrayOfTeams: arrayOfTeams,
usersGroupedByTeam: usersGroupedByTeam
});
}).fail(function(error){
//error handle
response.error(error.message);
});
I suggest you to return your result as an object, instead of an array. In your final result you will have the Teams (arrayOfTeams) and your users grouped by Team (usersGroupedByTeam).
And to retrieve specific team's users you will use usersGroupedByTeam["A_TEAM_ID"].
NOTE: remember that, by default, Parse.Query brings only 100 records. You could change it using Parse.limit, but don't forget to take this into account.
Related
Specifically, given a list of data, I want to loop over that list and do a fetch for each element of that data before I combine it all afterward. The thing is, as written, the code iterates through the entire list immediately, starting all the operations at once. Then, even though the fetch operations are still running, the then call I have after all that runs, before the data could've been processed.
I read something about putting all the Promises in an array, then passing that array to a Promise.all() call, followed by a then that will have access to all that processed data as intended, but I'm not sure how exactly to go about doing it in this case, since I have nested Promises in this for loop.
for(var i in repoData) {
var repoName = repoData[i].name;
var repoUrl = repoData[i].url;
(function(name, url) {
Promise.all([fetch(`https://api.github.com/repos/${username}/${repoData[i].name}/commits`),
fetch(`https://api.github.com/repos/${username}/${repoData[i].name}/pulls`)])
.then(function(results) {
Promise.all([results[0].json(), results[1].json()])
.then(function(json) {
//console.log(json[0]);
var commits = json[0];
var pulls = json[1];
var repo = {};
repo.name = name;
repo.url = url;
repo.commitCount = commits.length;
repo.pullRequestCount = pulls.length;
console.log(repo);
user.repositories.push(repo);
});
});
})(repoName, repoUrl);
}
}).then(function() {
var payload = new Object();
payload.user = user;
//console.log(payload);
//console.log(repoData[0]);
res.send(payload);
});
Generally when you need to run asynchronous operations for all of the items in an array, the answer is to use Promise.all(arr.map(...)) and this case appears to be no exception.
Also remember that you need to return values in your then callbacks in order to pass values on to the next then (or to the Promise.all aggregating everything).
When faced with a complex situation, it helps to break it down into smaller pieces. In this case, you can isolate the code to query data for a single repo into its own function. Once you've done that, the code to query data for all of them boils down to:
Promise.all(repoData.map(function (repoItem) {
return getDataForRepo(username, repoItem);
}))
Please try the following:
// function to query details for a single repo
function getDataForRepo(username, repoInfo) {
return Promise
.all([
fetch(`https://api.github.com/repos/${username}/${repoInfo.name}/commits`),
fetch(`https://api.github.com/repos/${username}/${repoInfo.name}/pulls`)
])
.then(function (results) {
return Promise.all([results[0].json(), results[1].json()])
})
.then(function (json) {
var commits = json[0];
var pulls = json[1];
var repo = {
name: repoInfo.name,
url: repoInfo.url,
commitCount: commits.length,
pullRequestCount: pulls.length
};
console.log(repo);
return repo;
});
}
Promise.all(repoData.map(function (repoItem) {
return getDataForRepo(username, repoItem);
})).then(function (retrievedRepoData) {
console.log(retrievedRepoData);
var payload = new Object();
payload.user = user;
//console.log(payload);
//console.log(repoData[0]);
res.send(payload);
});
i have a simple question and i have read a lot of same issues here, but these are not exact the same or doesn't work for me :-(
I have a REST function called "addevent". The function gets a json input (req) and iterate through the json array to get some IDs to store them in an extra Array. That works perfect!
After that, the function should search in a mongodb for every single id and store some extra informations from this ID (e.g. the stored URL of this ID). With "console.log(result.link)" it works again perfect. But my problem is that, that i need to store this link in an extra Array (urlArray).
So how can i save the result of collection.findone(). I read something about, that findone() doesn't return a document, but a cursor? what does that mean? How do i have to handle that in my case?
That's the code:
exports.addevent = function(req, res) {
var ids = req.body;
var pArray = new Array();
var urlArray = new Array();
var eventName = ids.name;
for(var i in ids.photos) {
photoArray.push(ids.photos[i]);
var id = ids.photos[i]._id;
var collection = db.get().collection('photos');
collection.findOne({'_id':new mongo.ObjectID(id)},function(err, result) {
console.log(result.link);
}
)
}
Many thanks!
-------------------- Update --------------------
Ok, i think that has something to do with the asynch Callbacks. I found an article, but i don't know how to implement it in my case.
http://tobyho.com/2011/11/02/callbacks-in-loops/
And something about "promises" in javascript.
You can save the result of your search doing something like:
var foundPhoto = collection.find({_id':new mongo.ObjectID(id)}, function(err, photo){
if(!err){
return photo;
} else {
console.log(err)
return null;
}
});
This way you get the return statement of your query in the "photo" variable.
In a Chrome extension im using the HTML5 FileSytem API.
Im retrieving a list of records in a folder.
var entries = [];
var metadata = [];
listFiles(folder);
function listFiles(fs) {
var dirReader = fs.createReader();
entries = [];
// Call the reader.readEntries() until no more results are returned.
var readEntries = function () {
dirReader.readEntries(function (results) {
if (!results.length) {
addMeta(entries);
} else {
console.log(results);
entries = entries.concat(toArray(results));
readEntries();
}
});
};
readEntries(); // Start reading dirs.
}
The FileEntry object does not contain metadata, I need the last modified date. I'm able to retrieve a object of metadata
function addMeta(entries) {
for (var i = 0; i < entries.length; i++) {
entries[i].getMetadata(function (metadata) {
console.log(entries);
console.log(metadata);
});
}
}
Problem is that i get the metadata in a callback.
How can i join the two object making sure the right match is made?
The simplified result im looking for is:
[
["fileName1", "modifyDate1"],
["fileName2", "modifyDate2"],
]
To get lastModifiedDate, you don't need to use getMetadata, as per the description of this question, just use entry.file.lastModifiedDate, though maybe file() is another callback.
To "join the two object making sure the right match is made", because of Closures, you could use the following code to get the right results. (Assuming the data structure is [[entry, metadata]] as you mentioned)
var ans = [];
function addMeta(entries) {
for (var i = 0; i < entries.length; i++) {
(function(entry) {
entry.getMetadata(function (metadata) {
ans.push([entry, metadata]);
});
}(entries[i]);
}
}
If what you want is to wait for all asynchronous callback ends, see this answer for more details, basically you could adjust your code and use Promise, or use other implementations like setInterval or use a variable to calculate how many callbacks remain.
I suggest to have a look on Promise-based bro-fs implementation of HTML Filesystem API.
To read all entries with metadata you can do something like this:
fs.readdir('dir')
.then(entries => {
const tasks = entries.map(entry => fs.stat(entry.fullPath))
return Promise.all(tasks);
})
.then(results => console.log(results))
I have a sub query in mongoose need to get array out of sub query and attach to main json out put/ object.
my first query get user info which contains blocked_users array which is nothing but array of user id's.
i my second query we get profile details of blocker_users array and append to main user object in blocked_users.
var userId = ObjectID(req.body.user_id);
//Get user
newUserModel.findById(userId, function(err, user){
if(err){
utils.getResponse(res, req.url, messages.failure, "");
} else {
var userInfo = {};
var blcked_contacts;
//get users details from blocked contacts userid's array
newUserModel.find({'_id': {$in:user.blocked_contacts}}, function (err,blocked_users) {
if(blocked_users){
//blcked_contacts.push(blocked_users);
console.log(blocked_users);
return;
};
/*else{
blcked_contacts = [];
}*/
});
userInfo['blocked_contacts'].push(blocked_users);
userInfo['user_id'] = user.id;
userInfo['country_code'] = user.country_code;
//userInfo['blocked_contacts'].push(blcked_contacts);
//userInfo['blocked_contacts'] = user.blocked_contacts;
var userData = Array();
}
});
Don't really know what you're looking for. But saw a problem in your code. You've assigned the blocked_users to the blocked_contacts field outside the find method.
Since these calls are asynchronous in nature, it might happen that the assignment takes place even before the documents are fetched from MongoDB. So you should write your assignment statements inside the find methods' callback, just the way Medet did.
Noticed few mistakes in your code like trying to use .push on an object. You cant do
userInfo['blocked_contacts'].push(blocked_users); // incorrect as userInfo is an empty object and you dont have an array defined for userInfo['blocked_contacts']
You probably get cannot push into undefined error for this. So instead do
userInfo['blocked_contacts'] = blocked_users;
Also you have to do this inside the second find() as blocked_users is only available inside it. So your final query should be something like
var userId = ObjectID(req.body.user_id);
//Get user
newUserModel.findById(userId, function(err, user){
if(err){
utils.getResponse(res, req.url, messages.failure, "");
} else {
var userInfo = {};
//get users details from blocked contacts userid's array
newUserModel.find({'_id': {$in:user.blocked_contacts}}, function (err,blocked_users) {
if(blocked_users){
userInfo['user_id'] = user.id;
userInfo['country_code'] = user.country_code;
userInfo['blocked_contacts'] = blocked_users; // assign blocked_users into userInfo
console.log(userInfo) // Your required object
} else {
userInfo['user_id'] = user.id;
userInfo['country_code'] = user.country_code;
userInfo['blocked_contacts'] = []; // assign null array if no blocked users fould
}
});
var userData = Array();
}
});
The result of console.log should be an object like this
{
user_id : "..id of searched user...",
country_code : "..country code of searched user..",
blocked_contacts : [<array containing detais of all blocked users>] // null array if no users found
}
I would like to make a collection of all elements that are selected and not.
The dom element consists of several multiple select.
Each of them have the same users.
My goal is to create a collection of all users and for the user which are selected add an attribute with a specific value.
Here is my code js code (1) and here is the link http://jsfiddle.net/vxRtb/9/.
My code works, but I would like to dry the code because, maybe, lopping just on the first select to get all the user is not required.
Any hints how to dry the following js code?
Please read the comments on the js code for more info; thanks
P.S.:
1) I am using jQuery and underscore
2) From the server I get the html code, the same as in jsfiddle.net/vxRtb/9
$(function () {
var $selectElements = $('form .controls select');
var userCollection = [];
// Subroutine_1
// TODO Subroutine_1 and Subroutine_2 seems too close; any idea how to dry this code?
$.each($($selectElements[0]), function (i, teamElement) {
var $users = $(teamElement).find('option')
$.each($users, function (i, user) {
userCollection.push({
id: $(user).val(),
name: $(user).text(),
});
});
});
// Subroutine_2
$.each($selectElements, function (i, teamElement) {
var $teamElement = $(teamElement);
//var teamId = $teamElement.attr('id');
var teamName = $teamElement
.parent().parent().closest('.controls')
.find('input').val();
var $users = $teamElement.find('option:selected');
$.each($users, function (i, user) {
_.where(userCollection, {id: $(user).val()})[0].team = teamName;
});
});
console.log(userCollection);
});
This is a fairly old question and you've probably moved on from it, however, I took a try at this and here's what I came up with.
Analysis
The loops are very similar with the key difference of one loop builds up the team members and the other loop figures out their team. I think the DRY option is to only use one loop and test if a member has a team or not. There will be repetition as the user id's are non-unique, so some logic needs to be applied.
Pseudo Code
Create User Object Collection based off of the <option> tag.
Use getMyTeam to generate the team name
Group the User Objects by ID.
Filter User Objects taking only those with a team names
Filter User Objects without team names to show only uniq records
Code
I'm not sure if this is any better. Performance-wise, this should be fairly poor due to all the nesting. However, I guess the advantage is that the code becomes much more modular and you can easily change the rules if needed. jsFiddle
$(function () {
// Helper to find a team based on an options element
function getMyTeam() {
if (this.is(':selected')) {
var select = this.parent();
var teamId = select.attr('id').replace(/_participations$/, '_name');
return $('#' + teamId).val();
}
return undefined;
};
// Helper to return an object's id
function getId(obj) {
return obj.id;
};
// Helper to filter the team members by team name.
function filterMembersByTeam(members) {
var result = _.filter(members, function(record) {
return !_.isUndefined(record['team']);
});
if (result.length === 0) {
result = _.uniq(members, true, function(member) {
return JSON.stringify(member);
})
};
return result;
};
// 1. Select the users
var options = $('form .controls select option');
// 2. Build up the user data
var userCollection = _.map(options,
function(option) {
return {
id: $(option).val(),
name: $(option).text(),
team: getMyTeam.apply($(option))
};
});
// 3. Clean & filter the user data
userCollection =
_.flatten(
_.map( _.groupBy(userCollection, getId), filterMembersByTeam)
);
console.log(userCollection);
});