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I'm building a web app with Vue.js using Firebase authentication and real time database, which I'm new to.
In this app the user answers to questions to achieve some points.
My problem is: I want to update an existing array already stored and created in the database so that the progress/points of that user will be under track to update all the components in my app.
For example let's say I want to increase +1 the highlighted value in the screenshot:
I was thinking about something like userid.progress[6][0] += 1 like in normal javascript, but I can't update the database, value still at 0.
I've read something about .set() or .update() but in that case I should rewrite all the array (and it would be a problem), but I might be completely wrong.
PS: it's not a problem about getting the user id or the current user, everything is working fine.
Hope to find someone to help me, thank you so much in advance!
If you're trying to update an existing score, you can write on the most granular level. So:
ref.child("pjoCy...0tl3/progress/0/6/0").set(1)
If you want to push a new score to the end of the array, you'll indeed need to read the entire score array to add a new value to the end. This is one of the many reasons why Firebase recommends against using array indices like you do. If you instead us so-called push-IDs, adding a new value becomes as easy as:
ref.child("pjoCy...0tl3/progress/0/6").push(1)
I recommend reading more about structuring lists in the Firebase documentation and the classic blog posts on handling arrays in Firebase.
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I am working with Angular, C# for the backend and DB with Oracle. The project is for a company and in the grids they leave me more than 120 records. In these grids the user can edit each record and by selecting the "Save" button all the records are sent (those that have been modified and those that have not been modified) and that is where I need your help. How can you tell which records have changed? MY IDEA is to make a copy of the data that arrives and at the end compare which ones have been changed and send that new list to the database (only with the changed records). ANOTHER IDEA is that every time someone makes a change, it will be added to another list, but the problem with this is how to identify when it changes and when it changes and returns to how it was ... Any ideas?
There are numerous ways to keep track of which elements have been modified:
Define an interface with the object and an "isModified" flag. As each item is modified, turn that flag to true.
Keep a separate list of modified objects (as you mentioned)
Keep a list of the Ids of the modified objects
With regard to how to determine whether an object has been changed, that will depend on how you are handling the edits. If you are using Angular Forms (as mentioned by #nobalG above), then it will tell you went the data is modified.
If not, again depending on how you are handling the edits, you may have other changed events you can track.
More detail isn't possible without having some code detailing how you are handling the edits.
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I've tried a lot of ways, like for example the fs module, but I just can't find out how to implement this. I need a button that:
Updates by one whenever any user presses the button
Persists on the server
Does anyone know how to do this?
If you are new and need to build something that stores stuff on the server you have a lot to learn. If you just need to solve this simple problem and get things working you could make huge progress using a hosted backend service. If you do this you can write a couple of lines in JS and the job will be done. Most offer a free account.
One such service is built.io see link below:
https://docs.built.io/api-reference
var project = Built.App('blt5d4sample2633b').Class('score').Object();
project = project.increment('points',10); //Increases points field value by 10
That code above would update the score by 10 and store it , you can then retreive it when you show the page. All users would see the score update.
There are realtime backend services too which are very good.
An example is:
www.firebase.com
You would need to decide which one is best for you, add their script to your page add a button, hook the click event upto a function that you would then add the simple code to update the score. See above.
It a nutshell that would be it. You can probably get it working in under 1 hour if you follow the guides on the vendors site.
Firebase is backed by google and has a huge online community.
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*not looking for code to be provided, just want to know if its possible.
For example. I have an h2 class named "stock-number" and its value is #NC123456. Can javascript read each instance of that class, fetch data from another database using that value, and display the results in another class.
Real world example would be if I sold TVs. The TV has an msrp and inventory is retrieved from one database. However, we can set a sale price. and the discounts and rebates are from another database, sorted by that tvs stock number.
Can I read that stock number, pull the pricing break down from the other database, and display in back into the page underneath the sale price in its own div so customers understand their savings?
Yes, it can.
In order to do the database lookup, receive the returned data, and update the DOM with new data, you also need to use AJAX.
Basic ajax tutorial
You might also want to compare jQuery code to the above pure javascript code -- most folks find jQuery a lot faster/easier (especially with AJAX).
jQuery is a library that runs on top of javascript and all that is required in order to use it is to include the library somewhere on the page:
<head>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.2/jquery.min.js"></script>
</head>
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I have 10 records in json array that comes from api call. But I need to show only 1 record on webpage providing next and previous buttons. So when user clicks on next or previous buttons I need to fetch the next or previous records and display on webpage. Something like viewpager in android or flipview in windows apps.
The reason why I want to store is just to avoid unnecessarily api calls to server fetching record and also pointers to next and previous record.
Is it possible to store those 10 records in some javascript variable and keep iterating when user clicks on next and previous.
Server side I am using laravel 5.2
Of course it can be done. Just format your JSON correctly to hold an array of records, and maintain an index pointing to the current record.
To update the display you can either use pure JavaScript or utilize some kind of MVVM library (for example) like Knockout or Angular.
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I'm required to implement a notification system integrated to a web application (JavaScript + PHP). Notifications should be fired based on user-defined rules. I don't have experience with rules engines and building rules. Therefore, I don't know what I'm doing or if what the following could be implemented by better solution.
I'm trying to figure out how to store and process the following hypothetical scenario. Let's say that the web app is a shopping online service for a store that has 3 lines of products, line A, line B and line C. Each line has different characteristics. User#1 selects an object from line A, then specifies some characteristics such as size and colors. User#2 selects an object from line B, the only characteristic for this kind is material, he selects wood. Then both users ask system to notify them whenever these objects with these characteristics become available.
From what I've read so far, this could be done through [user-defined rules]. If so, then
What's the best technology to handle it? I'm willing to learn but I need a direction to help me start.
Can I use openRules or similar for this?
How to sent user defined data to a web service? given that they change based on the line.
If you are using a database, or anything similar, you can make a table where you would save the rules for each user. You can than later load them with a php class as soon as the user logs in, and check against them before doing anything that was optional.
You can also make a table and set flags, once an item becomes available loop trough the table and notify every user waiting. You would need to store, item id and customer id, in the table and delete them once they have been notify.