Appending to an object

Question

I have an object that holds alerts and some information about them   var alerts          1    app   helloworld   message   message         2    app   helloagain   message   another message        In addition to this  I have a variable that says how many alerts there are  alertNo  My question is  when I go to add a new alert  is there a way to append the alert onto the alerts object

User · Answer

Now with ES6 we have a very powerful spread operator (...Object) which can make this job very easy. It can be done as follows:

let alerts = { 
   1: { app: 'helloworld', message: 'message' },
   2: { app: 'helloagain', message: 'another message' }
} 

//now suppose you want to add another key called alertNo. with value 2 in the alerts object. 

alerts = {
   ...alerts,
   alertNo: 2
 }

Thats it. It will add the key you want. Hope this helps!!

User · Answer

Try this   alerts splice 0 0   app   goodbyeworld   message   cya       Works pretty well  it ll add it to the start of the array

User · Answer

How about storing the alerts as records in an array instead of properties of a single object     var alerts           num   1  app  helloworld  message  message         num   2  app  helloagain  message  another message        And then to add one  just use push   alerts push  num   3  app  helloagain again  message  yet another message

User · Answer

You can use spread syntax as follows    var alerts      1    app   helloworld   message   message     2    app   helloagain   message   another message        alerts       alerts  3   app   hey there   message   another message

User · Answer

Javascript  After a bit of jiggery pokery  this worked for me    let dateEvents                                    Count   2                   Items                                                    LastPostedDateTime                                  S    10 16 2019 11 04 59                                                                                                  LastPostedDateTime                                  S    10 30 2019 21 41 39                                                                                                      console log  dateEvents   dateEvents     The problem I needed to solve was that I might have any number of events and they would all have the same name  LastPostedDateTime all that is different is the date and time

User · Answer

You should really go with the array of alerts suggestions  but otherwise adding to the object you mentioned would look like this   alerts 3    app   goodbyeworld   message   cya      But since you shouldn t use literal numbers as names quote everything and go with  alerts  3     app   goodbyeworld   message   cya      or you can make it an array of objects   Accessing it looks like  alerts  1   app   gt   helloworld

User · Answer

I m sorry but i can t comment your answers already due my reputation    so  if you wanna modify the structure of your object  you must do like Thane Plummer says  but a little trick if you do not care where to put the item  it will be inserted on first position if you don t specify the number for the insertion   This is wonderful if you want to pass a Json object for instance to a mongoDB function call and insert a new key inside the conditions you receive  In this case I gonna insert a item myUid with some info from a variable inside my code    x000D   x000D     From backend or anywhere x000D  let myUid      id   userid128344    x000D        x000D        x000D   x000D    let myrequest      id   5d8c94a9f629620ea54ccaea    x000D    const answer   findWithUid  myrequest  exec    x000D   x000D        x000D        x000D   x000D  function findWithUid  conditions    x000D    const cond uid   Object assign  uid  myUid   conditions   x000D       the object cond uid now is  x000D        uid   userid128344    id   5d8c94a9f629620ea54ccaea   x000D       so you can pass the new object Json completly with the new key x000D    return myModel find cond uid  exec    x000D    x000D   x000D   x000D

User · Answer

Way easier with ES6    x000D   x000D  let exampleObj     x000D    arg1    x000D      subArg1  1  x000D      subArg2  2  x000D       x000D    arg2    x000D      subArg1  1  x000D      subArg2  2  x000D      x000D     x000D   x000D  exampleObj arg3     x000D    subArg1  1  x000D    subArg2  2  x000D     x000D   x000D  console log exampleObj   x000D   x000D   x000D      arg1   subArg1  1  subArg2  2  arg2   subArg1  1  subArg2  2  arg3   subArg1  1  subArg2  2

User · Answer

Do you have the ability to change the outer-most structure to an array   So it would look like this  var alerts      app   helloworld   message  null    app   helloagain   message   another message       So when you needed to add one  you can just push it onto the array  alerts push    app   goodbyeworld   message   cya        Then you have a built-in zero-based index for how the errors are enumerated

User · Answer

You can do this with Object assign    Sometimes you need an array  but when working with functions that expect a single JSON object -- such as an OData call -- I ve found this method simpler than creating an array only to unpack it   var alerts          1   app  helloworld  message  message        2   app  helloagain  message  another message      alerts   Object assign  3   app  helloagain again  message  yet another message     alerts     Result  console log alerts         1   app  helloworld  message  message        2   app  helloagain  message  another message       3   app   helloagain again  message   yet another message        EDIT  To address the comment regarding getting the next key  you can get an array of the keys with the Object keys   function -- see Vadi s answer for an example of incrementing the key  Similarly  you can get all the values with Object values   and key-values pairs with Object entries     var alerts          1   app  helloworld  message  message        2   app  helloagain  message  another message     console log Object keys alerts      Output Array    1    2

User · Answer

As an alternative  in ES6  spread syntax might be used    Object keys alerts  length   1  returns next id for alert     x000D   x000D  let alerts      x000D      1   app  helloworld  message  message    x000D      2   app  helloagain  message  another message   x000D     x000D   x000D  alerts     x000D       alerts   x000D        Object keys alerts  length   1      x000D       x000D      app   helloagain  Object keys alerts  length   1   message   next message   x000D       x000D     x000D   x000D  console log alerts   x000D   x000D   x000D

User · Answer

Like other answers pointed out  you might find it easier to work with an array    If not   var alerts          1   app  helloworld  message  message        2   app  helloagain  message  another message         Get the current size of the object size   Object keys alerts  length    add a new alert  alerts size   1     app  Your new app   message  your new message      Result  console log alerts         1   app  helloworld  message  message        2   app  helloagain  message  another message       3   app   Another hello  message   Another message             try it   https   jsbin com yogimo edit js console

User · Answer

jQuery   extend obj1  obj2  would merge 2 objects for you  but you should really be using an array   var alertsObj         1   app  helloworld   message        2   app  helloagain  message  another message       var alertArr          app  helloworld   message         app  helloagain  message  another message       var newAlert    app  new  message  message       extend alertsObj  newAlert   alertArr push newAlert

[javascript] Appending to an object

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