Develop Reference

Steam trade-offer-manager get items info shorten

I'm trying to build a new project.
It's going to be a tradebot for a website, now to store my received items into my database i whould like some info send with each item (being the name , asseid , tradeid,...).
The following code works.
offers.on('receivedOfferChanged', function (offer, oldState) {
logger.info(offer.partner.getSteam3RenderedID() + " Offer #" + offer.id + " changed: " + TradeOfferManager.getStateName(oldState) + " -> " + TradeOfferManager.getStateName(offer.state));
// Alert us when we accept an offer
if (offer.state == TradeOfferManager.ETradeOfferState.Accepted) {
offer.getReceivedItems(function (err, items) {
if (err) {
logger.error("Couldn't get received items: " + err);
} else {
var names = items.map(function(item) {
return item.name;
});
var assetids = items.map(function(item) {
return item.assetid;
});
// Log a comma-separated list of items received
logger.info("Received: " + names + " " + assetids.join(', '));
}
});
}
});`
But the thing is, is there any way to shorten the following code :
var names = items.map(function(item) {
return item.name;
});
var assetids = items.map(function(item) {
return item.assetid;
});
So it gets the item name , assetid, ... out of the array and stores them in sperate variables ?

You can use push() method to add values into both arrays in a single loop. Try:
var names = [],
assetids = [];
items.forEach(function(item) {
assetids.push(item.assetid);
names.push(item.name);
});

How to fetch or convert Parse query into array (JavaScript SDK)

I have a column in my Parse database populated with numbers and I'm trying to add them all together to get a total.
I know how to do the adding together if the data returned is a single array, but I can only figure out how to return the numbers as individual objects. This is my code which does that:
var query = new Parse.Query(Services);
query.exists("costMonthly");
query.find({
success: function (results) {
for (var i = 0; i < results.length; i++) {
var object = results[i];
console.log(object.get('costMonthly'));
}
},
error: function (error) {
alert("Error: " + error.code + " " + error.message);
}
});
How would I go about fetching what I want as an array or at least converting what I have into one?

It looks like you are trying to sum the costMonthly field. You can use reduce to do this easily:
var query = new Parse.Query(Services);
query.exists("costMonthly");
query.find({
success: function (results) {
var sum = results.reduce(function(prev, cur) {
return prev + cur.get('costMonthly');
}, 0);
},
error: function (error) {
alert("Error: " + error.code + " " + error.message);
}
});
If your goal is an array of the costMonthly values, this will work:
var monthlyCosts = results.map(function(item) {
return item.get('costMonthly');
});
Read more about reduce here: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/Reduce

You can create a temporary array , and push results though through iteration , not the best solution , but is very useful if you want to manipulate results later :
var costMonthlyArray=[];
var query = new Parse.Query(Services);
query.exists("costMonthly");
query.find({
success: function (results) {
for (var i = 0; i < results.length; i++) {
var object = results[i];
var cost=object.get('costMonthly');
costMonthlyArray.push(cost);
console.log(cost);
}
},
error: function (error) {
alert("Error: " + error.code + " " + error.message);
}
});

how to run javascript object from string without using eval()

i have a json object that has item type and id, i need to create new object
var data = {
"items":[
{"type":"generator","id":"item_1","x":200,"y":200},
{"type":"battery","id":"item_2","x":50,"y":300},
{"type":"generator","id":"item_3","x":200,"y":280},
{"type":"battery","id":"item_4","x":100,"y":400}
]
};
and i need to run for each item in items
jQuery.each(data.items, function(index,value) {
eval("var " + value.id + " = new " + value.type + "(" + (index + 1) + ");");
eval(value.id + ".id = '" + value.id + "';");
eval(value.id + ".draw(" + value.x + "," + value.y + ");")
});
this is not a good practice, but what else can i do?
i need then to have the control on the items
something like
item_1.moveto(300,700);
but i always get item_1 is undefind

You can create a factory method which allows to generate concrete types out of an abstract data structure:
var createItem = (function () {
var types = {};
function createItem(index, data) {
data = data || {};
var ctor = types[data.type], item;
if (!ctor) throw new Error("'" + data.type + "' is not a registered item type.");
item = new ctor(index);
item.id = data.id;
return item;
}
createItem.registerType = function (type, ctor) {
types[type] = ctor;
};
return createItem;
})();
Then register item types to the factory:
function Generator(index) {/*...*/}
createItem.registerType('generator', Generator);
And finally create an object map to lookup your items by id (you could use a specialized object like ItemsMap instead of a plain object), loop through your items and add them to the map.
var itemsMap = {};
data.items.forEach(function (itemData, i) {
var item = itemsMap[itemData.id] = createItem(i + 1, itemData);
//you can also draw them at this point
item.draw(itemData.x, itemData.y);
});
You can now lookup objects by id like:
var item1 = itemsMap['item_1'];

var objects = {};
objects[value.id] = new window[value.type](index + 1);

Query Parent and child data in one call - parse.com + javascript

I am trying to understand how to query related classes in one call from parse.com using javascript.
I have 2 classes Post and Comment. Post has a column of type relation named 'Comment' and Comment has a column 'parent' of type pointer.
I use the following following code based on parse docs, to save a post and related comment
var Post = Parse.Object.extend("Post");
var Comment = Parse.Object.extend("Comment");
//Create the post
var myPost = new Post();
myPost.set("title", "I'm Hungry");
myPost.set("content", "Where should we go for lunch?");
// Create the comment
var myComment = new Comment();
myComment.set("text", "Let's do subway.");
myComment.set("parent", myPost);
myComment.save();
I am trying to query data like this
var query = new Parse.Query("Post");
query.descending("createdAt");
query.find({
success: function(results) {
for(var i = 0; i < results.length; i++) {
var post = results[i];
var relation = post.relation('Comment');
relation.query().find({
success: function(comments) {
for(var j = 0; j < comments.length; j++) {
console.log(comments[j].get("content"));
}
}
});
}
},
error: function(error) {
alert("Error: " + error.code + " " + error.message);
}
});
Can anybody tell me what i am doing wrong here?

The problem in your code is that you're not setting up the relation between the post and the comment. Without that relation setup your query won't work. Here's the working code. Note that I have to save the comments before creating the relation, otherwise you'll get an error from parse.
function createPost() {
var Post = Parse.Object.extend("Post");
var Comment = Parse.Object.extend("Comment");
//Create the post
var myPost = new Post();
myPost.set("title", "I'm Hungry");
myPost.set("content", "Where should we go for lunch?");
// Create the comment
var comment1 = new Comment();
comment1.set("text", "Let's do subway.");
comment1.set("parent", myPost);
var comment2 = new Comment();
comment2.set("text", "Let's do Hoagies.");
comment2.set("parent", myPost);
return Parse.Object.saveAll([comment1, comment2]).then(function() {
// Set the relationship
var relation = myPost.relation('comments');
relation.add(comment1);
relation.add(comment2);
return myPost.save();
});
}
createPost().then(function() {
var query = new Parse.Query("Post");
query.descending("createdAt");
var posts = [];
return query.find().then(function(results) {
var promises = [];
for(var i = 0; i < results.length; i++) {
var post = results[i];
var relation = post.relation('comments');
var postData = { post : post, comments : [] };
posts.push(postData);
console.log("Post : " + post.get('title'));
promises.push(relation.query().find({
success: function(comments) {
for(var j = 0; j < comments.length; j++) {
console.log("Comment " + j + " : " + comments[j].get("text"));
postData.comments.push(comments[j]);
}
}
}));
}
return Parse.Promise.when(promises);
},
function(error) {
alert("Error: " + error.code + " " + error.message);
}
).then(function() {
console.log(posts);
return posts;
});
})

Node.js with Restler to return a value?

This is very early in my Node and JavaScript learning. Ideally, what I am attempting to do is create a small module querying a specific type of rest endpoint and returning a specific feature based on an attribute query. The module is correctly logging out the result, but I am struggling to get the .findById function to return this result. Although aware it has something to do with how the callbacks are working, I am not experienced enough to be able to sort it out yet. Any help, advice and direction towards explaning the solution is greatly appreciated.
// import modules
var restler = require('restler');
// utility for padding zeros so the queries work
function padZeros(number, size) {
var string = number + "";
while (string.length < size) string = "0" + string;
return string;
}
// create feature service object
var FeatureService = function (url, fields) {
// save the parameters
this.restEndpoint = url;
this.fields = fields;
var self = this;
this.findById = function (idField, value, padZeroLength) {
var options = {
query: {
where: idField + '=\'' + padZeros(value, padZeroLength) + '\'',
outFields: this.fields,
f: "pjson"
},
parsers: 'parsers.json'
};
var url = this.restEndpoint + '/query';
restler.get(url, options).on('complete', function(result){
if (result instanceof Error){
console.log('Error:', result.message);
} else {
console.log(result); // this log result works
self.feature = JSON.parse(result);
}
});
return self.feature;
};
};
var restEndpoint = 'http://services.arcgis.com/SgB3dZDkkUxpEHxu/ArcGIS/rest/services/aw_accesses_20140712b/FeatureServer/1';
var fields = 'nameRiver,nameSection,nameSectionCommon,difficulty,diffMax';
var putins = new FeatureService(restEndpoint, fields);
var feature = putins.findById('awid_string', 1143, 8);
console.log(feature); // this log result does not
//console.log('River: ' + feature.attributes.nameRiver);
//console.log('Section: ' + feature.attributes.nameSection + ' (' + feature.attributes.nameSectionCommon + ')');
//console.log('Difficulty: ' + feature.attributes.difficulty);

So, I sorted out how to insert a callback from a previous thread. It appears it is just passed in as a variable and called with expected parameters. However, I now wonder if there is a better way to accept parameters, possibly in the form of options. Any advice in this regard?
// import modules
var restler = require('restler');
// utility for padding zeros so the queries work
function padZeros(number, size) {
var string = number + "";
while (string.length < size) string = "0" + string;
return string;
}
// create feature service object
var FeatureService = function (url, fields) {
// save the parameters
this.restEndpoint = url;
this.fields = fields;
var self = this;
// find and return single feature by a unique value
this.findById = function (idField, value, padZeroLength, callback) {
// query options for
var options = {
query: {
where: idField + '=\'' + padZeros(value, padZeroLength) + '\'',
outFields: this.fields,
f: "pjson"
},
parsers: 'parsers.json'
};
var url = this.restEndpoint + '/query';
restler.get(url, options)
.on('success', function(data, response){
var dataObj = JSON.parse(data).features[0];
console.log(dataObj);
callback(dataObj);
})
.on('fail', function(data, response){
console.log('Error:', data.message);
});
return self.feature;
};
};
var restEndpoint = 'http://services.arcgis.com/SgB3dZDkkUxpEHxu/ArcGIS/rest/services/aw_accesses_20140712b/FeatureServer/1';
var fields = 'nameRiver,nameSection,nameSectionCommon,difficulty,diffMax';
var putins = new FeatureService(restEndpoint, fields);
putins.findById('awid_string', 1143, 8, function(dataObject){
console.log('River: ' + dataObject.attributes.nameRiver);
console.log('Section: ' + dataObject.attributes.nameSection + ' (' + dataObject.attributes.nameSectionCommon + ')');
console.log('Difficulty: ' + dataObject.attributes.difficulty);
});