I am trying to add "ProductName":"TRUE/FALSE" to my database, but when I add another (using javascript), it just removes the previous one, and adds the new one.
Here is my code:
database.ref(`product-whitelist`).child(Id).set({
[productname]: "TRUE"
});
But whenever this is run again, and "productname" has changed, it removes the previous one that was made.
If anyone knows how I can fix this, please let me know!
You're looking for the update() method:
database.ref(`product-whitelist`).child(Id).update({
[productname]: "TRUE"
});
This will write the value of [productname] and leave other properties under child(Id) untouched.
The above code is equivalent to:
database.ref(`product-whitelist`).child(Id).child(productname).set("TRUE");
But this approach can only write one property. By using update you can set some properties, while leave others untouched.
Try this,
database.ref(`product-whitelist\`+Id).child(productname).set({
[productname]: "TRUE"
});
Related
in my code I was always doing
for(i in vector)...
and it always worked, but the problem is that it somehow changed and now my for shows all the values but also the properties, like "remove" that is a function, and it is breaking my whole code.
I don't know why it suddenly changed, because I didn't do anything and I'm getting crazy with this already.
Do you guys know what is happening with my application?
Another thing is that the code only get this problem on my computer.
If I clone my repository again and try it works for while but then starts the problem again.
Thank you.
The in operator has always had this behaviour. Just check that the property exists directly on the object instead of on the prototype:
for (var i in vector) {
if (vector.hasOwnProperty(i)) {
// Property exists on object
}
}
That should solve your issues.
Tom
I have been trying for getting an id from localStorage but unable to achieve it.
My localStorage inside events contains such as below.
[{"id":"ef5","title":"wan","start":"2016-05-12","end":"2016-05-13"},{"id":"ef6","title":"wana","start":"2016-05-21","end":"2016-05-22"},{"id":"ef7","title":"haha","start":"2016-05-25","end":"2016-05-26"},{"id":"ef8","title":"asdas","start":"2016-05-20","end":"2016-05-21"},{"id":"ef9","title":"sdas","start":"2016-05-19","end":"2016-05-20"}]
Now i will provide 2 coding with different method that i have tried so far. For information, i look through into this topic: localstorage: Get specific localstorage value of which contains many items
but none works for me.
I did tried coding as below:
1st method:
$("#deleteEventYes").click(function(){
var indexDel = localStorage.getItem("events");
var deleteId = calEvent.id;
var result = localStorage.getItem("events");
function getItemHrefById(json, itemId){
return $(json).filter(function(){return this.id == itemId;})[0].href;
}
var href = getItemHrefById(result, deleteId);
alert(href); });
Above code show some kind of array method (i think) where i'm using indexDel to get item from localStorage (events) while deleteId i took from calEvent.id which is the id for the event that has been clicked for to be deleted. Other than that, i think you guys know what it is. However for this method, i use result variable instead of indexDel. Thus don't mind if i getItem from localStorage 2 times
2nd method:
for (var i = 0 ; i < indexDel.length ; i += 1) {
if(deleteId == indexDel[i].id) {
return indexDel[i];
console.log(deleteId);
console.log(indexDel[i]);
}
}
return null;
Above code is using custom loop i think. The declaration of variable for indexDel is still the same with first method. I try to use the refactoring method but it seems its hard for me to understand how is it to be done. Is it because my variable placement is wrong? or is it because it is not suitable for my case?
NOTE: I want to delete an event inside eventClick function, and so far i did retrieve the id and remove the event from the calendar based on id. However my only problem now is to match the deleted event id with the id inside my localStorage and remove the item. So far getting an id from the is quite complicated for me.
UPDATED
I already done something like this but still don't work. Anyone can tell me what went wrong here? It is not giving me any error but it just do nothing. Not even delete.
https://jsfiddle.net/v35a2o07/3/
Never mind. I think i figure it out :)
It is because i forgot to setItem & stringify it after using splice.
Here i can assume splice is the same as add/remove such wrote at w3school
http://www.w3schools.com/jsref/jsref_splice.asp
"The splice() method adds/removes items to/from an array, and returns the removed item(s)."
My final code is on this fiddle given: https://jsfiddle.net/v35a2o07/4/
So the concept is:
1) First step is declare one variable that parse your localStorage key such asvar items = JSON.parse(localStorage["events"]); so that you can use it for the loop
2) Use for loop to determine the length of localStorage based on localStorage key that we parse on No. 1
3) Use if statement to check the comparison between localStorage data with our desire data such as if(items[i].id == deleteId){
4) This is OPTIONAL but important. To enable you to check the comparison is right, create one alert or console.log() and stringify it because if you don't, you will only see [object,object]. The coding such as alert(JSON.stringify(items[i])+"<<<>>>"+deleteId); Make some else statement too if you want to be sure.
5) When all the conditions are correct, then you are ready to do some action to it. For my case, i just use splice() to delete it. It is also can be used to add item. I am not sure how is it done but try to search for it to get more info.
6) After splicing it, it is safely to break and get out from the loop.
7) This is important otherwise, it will not work. Don't forget to set it back to localStorage and stringify it such as localStorage.setItem('events', JSON.stringify(items));
That's it.
I wish this would help anyone that needs it. If i have make wrong statement or wrong concept, please make correction and clarify it for anyone.
Cheers.
I am trying to get the referrer and update the referrer so that my users can go back to the page they came back from. I have a hidden input field which holds the value of the redirect. I have a static value in there just in case the referrer is empty. If the referrer is not empty, I want to update the value of it. Here is the code I have written, I even tested it and it said it was updated, however, I am not being redirected properly, so it is not working.
JavaScript and HTML I have written (keep in mind, I have correctly linked the file and such):
$(document).ready(function(){
if (document.referrer != "") {
document.getElementsByName("redirect").value = document.referrer;
var test = "false";
if (document.getElementsByName("redirect").value == document.referrer){
test = "true";
}
alert(test);
}
});
<script src="js/referrer.js"></script>
<input type="hidden" name="redirect" value="https://www.google.com" />
I feel like this is a minor error or there might be some sort of standard I am not following.
Thanks for the help! I appreciate any insight!
I can't see what the problem is off hand by what you've given me. But what I can say is that if you are going to use JQuery in one place (document ready function) then you should also use it to grab the value of your input field.
It would also help if you put an Id on the input field instead of doing it by name. Ids are the best way to get a specific element. That could be your problem too.
Then call it using:
$("#ID").val()
so your code would become:
if($("#ID").val() === document.referrer)
I would also suggest using triple equals as well. But that is completely up to you.
I've never done anything with document.referrer, but there might be a better way of doing that as well.
One odd thing is that you are setting these 2 things equal to each other
document.getElementsByName("redirect").value = document.referrer;
and then immediately testing if they're equal to each other.
if (document.getElementsByName("redirect").value == document.referrer)
I can't say that this is your issue, but it's bad coding and should be fixed.
I think a single letter is tripping you up here.
if (document.getElement**s**ByName("redirect").value == document.referrer){
There's no singular equivalent for 'byName', so you do end up with an array (or at least, an array-like object). Unlike IDs, it is allowable for multiple inputs to have the same name. The easiest solution is this:
if (document.getElementsByName("redirect")[0].value == document.referrer){
Doing document.getElementsByName will return an object array that DOES NOT include the value. There is no way to change the value (That I know of and have tried) when using the getElementsByName. I have solved this issue by using getElementById, it actually works properly for me.
I want to detect a change in a new record. However, the record is new and dirty from the moment I create it.
var record = transaction.createRecord(App.ContentOfSomeSort, data);
record.get('isNew'); // true
record.get('isDirty'); // true
Is there an event or property that I can observe/listen for that tells me when the record has changed? I would think that isDirty would be good for this, but it's dirty as soon as I create it.
It looks like didSetProperty might be what you are looking for
https://github.com/emberjs/data/blob/master/packages/ember-data/lib/system/model/attributes.js#L65
Object.keys(model.changedAttributes()).length === 0 will work if you're just checking for plain attributes. changedAttributes() has an open issue right now where it will not report if relationships on the model have been changed.
I don't know ember.js (maybe there's some native function/event in it?), but can't it be done by setting interval which compares previous record value with actual one?
Firstoff I'd like to add I've been learning javascript for like only 2 days now. I'm pretty much way ahead of myself with what I'm trying to get but here goes.
I have a json array from which I get data to replace/insert in my page. The first problem I have is that if it comes across an empty ('null') key it will just stop. Will not even try to continu.
document.getElementById("id1")src=json.img1.link;
document.getElementById("id2")src=json.img2.link;
document.getElementById("id3")src=json.img3.link;
json.img2.link is empty ('null' response from json.). javascript will then not replace "id2" but it also won't replace "id3".
I'm now trying to find a solution where it will if nothing else at least set a default.
The script is not continuing executing because it comes to an error --trying to access property link of an undefined object
Try
document.getElementById('id2').src = json.img2 ? json.img2.link : 'defaultLink';
This way your are checking for undefined (ie null) object in img2 and assigning the default value. This assumes that what is not defined (null) is the img2 object.
Actually I don't think your code should work at all, you are missing the. before the src So, try
document.getElementById("id1").src=json.img1.link;
document.getElementById("id2").src=json.img2.link;
document.getElementById("id3").src=json.img3.link;
and let us know if that doesn't solve the problem.
Btw, +points for learning JavaScript and not just straight into jQuery!