How to sort value inside a Firebase child to the rest?
Firebase doesn't have a date type, since JSON doesn't have it. So it has no idea that there're stored dates in those strings. For sorting purposes you have to store a primitive type that represents these dates and gives required order of sorting when compared as a string or number.
For example: a timestamp. Given date
is a JS date object, add sortDate: date.getTime()
to each object when saving.
{
"events": {
"-JscIDsctxSa2QmMK4Mv": {
"date": "Friday, June 19, 2015",
"sortDate": 1434697200000,
"title": "Event Two"
},
"-Jswff0o9bWJeDmUoSA9": {
"date": "Friday, June 12, 2015",
"sortDate": 1434092400000,
"title": "Event One"
},
"-JscIs_oMCJ9aT6-JWDg": {
"date": "Monday, August 10, 2015",
"sortDate": 1439190000000,
"title": "Event Three"
}
}
}
And then:
ref.orderByChild("sortDate")...
Ricek
My name is Liang Gao. I'm a student from New York City, ever since I can remember I have loved technology. Please feel free to check-out my projects on GitHub. More information can be found through LinkedIn or send me an email.
Updated on June 29, 2022Comments
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Ricek almost 2 years
In my firebase I have several events, each with title and date string:
{ "events": { "-JscIDsctxSa2QmMK4Mv": { "date": "Friday, June 19, 2015", "title": "Event Two" }, "-Jswff0o9bWJeDmUoSA9": { "date": "Friday, June 12, 2015", "title": "Event One" }, "-JscIs_oMCJ9aT6-JWDg": { "date": "Monday, August 10, 2015", "title": "Event Three" } } }
In my javascript code, I retrieve the
events
child and push each title and date to an array then append it to my html page and display the content.var ref = new Firebase("https://demo.firebaseio.com/events"); var build = new Array(""); ref.orderByChild("date").once("value", function(snapshot) { snapshot.forEach(function(data) { var tmp = data.val(); eventMonth = tmp.date.split(" ")[1]; build.push('<h3>'+tmp.title+'</h3><p>Date: '+tmp.date+'</p>'); }); $("#event-content").append(build.join(''));
orderByChild
doesn't seem to be working, how can I order the events by date so it can look something like below:Event One: Friday, June 12, 2015
Event Two: Friday, June 19, 2015
Event Three: Monday, August 10, 2015