Nested JSON How to add push new items to an object

Question

I m just starting with Arrays  Objects  and JSON - so hopefully there s just something simple I m overlooking here  I m encountering an error when attempting to add  push  a new item into my json object   I m encountering the following error  Result of expression  library push   undefined  is not a function  towards the bottom of my code snippet       This is my JSON object generated from a database var library          Gold Rush               foregrounds      Slide 1   Slide 2   Slide 3             backgrounds      1 jpg      2 jpg               California               foregrounds      Slide 1   Slide 2   Slide 3             backgrounds      3 jpg   4 jpg   5 jpg               These will be dynamically generated vars from editor var title    Gold Rush   var foregrounds     Howdy   Slide 2    var backgrounds     1 jpg        function save              If title already exists  modify item     if  library title                Replace values with new         library title  foregrounds   foregrounds          library title  backgrounds   backgrounds              Save to Database  Then on callback            document write  Changes Saved to  lt b gt   title   lt  b gt             If title does not exist  add new item     else              Format it for the JSON object         var item        title        foregrounds      foregrounds    backgrounds      backgrounds                    THE PROBLEM SEEMS TO BE HERE              Error   Result of expression  library push   undefined  is not a function          library push item                Save to Database  Then on callback            document write  Added   lt b gt   title   lt  b gt              save

User · Answer

If your JSON is without key you can do it like this:

library[library.length] = {"foregrounds" : foregrounds,"backgrounds" : backgrounds};

So, try this:

var library = {[{
    "title"       : "Gold Rush",
        "foregrounds" : ["Slide 1","Slide 2","Slide 3"],
        "backgrounds" : ["1.jpg","","2.jpg"]
    }, {
    "title"       : California",
        "foregrounds" : ["Slide 1","Slide 2","Slide 3"],
        "backgrounds" : ["3.jpg","4.jpg","5.jpg"]
    }]
}

Then:

library[library.length] = {"title" : "Gold Rush", "foregrounds" : ["Howdy","Slide 2"], "backgrounds" : ["1.jpg",""]};

User · Answer

push is an Array method  for json object you may need to define it  this should do it   library title      foregrounds    foregrounds  backgrounds    backgrounds

User · Answer

library is an object  not an array  You push things onto arrays  Unlike PHP  Javascript makes a distinction   Your code tries to make a string that looks like the source code for a key-value pair  and then  push  it onto the object  That s not even close to how it works   What you want to do is add a new key-value pair to the object  where the key is the title and the value is another object  That looks like this   library title      foregrounds    foregrounds   backgrounds    backgrounds      JSON object  is a vague term  You must be careful to distinguish between an actual object in memory in your program  and a fragment of text that is in JSON format

User · Answer

You can achieve this using Lodash   assign function   library title      assign       foregrounds   foregrounds      backgrounds   backgrounds        x000D   x000D     This is my JSON object generated from a database x000D  var library     x000D     Gold Rush     x000D       foregrounds     Slide 1    Slide 2    Slide 3    x000D       backgrounds     1 jpg        2 jpg   x000D       x000D     California     x000D       foregrounds     Slide 1    Slide 2    Slide 3    x000D       backgrounds     3 jpg    4 jpg    5 jpg   x000D      x000D    x000D   x000D     These will be dynamically generated vars from editor x000D  var title    Gold Rush   x000D  var foregrounds     Howdy    Slide 2    x000D  var backgrounds     1 jpg        x000D   x000D  function save     x000D   x000D       If title already exists  modify item x000D    if  library title     x000D   x000D         override one Object with the values of another  lodash  x000D      library title      assign       x000D         foregrounds   foregrounds x000D           x000D         backgrounds   backgrounds x000D          x000D      console log library title    x000D   x000D         Save to Database  Then on callback    x000D         console log  Changes Saved to  lt b gt     title     lt  b gt     x000D      x000D   x000D       If title does not exist  add new item x000D    else   x000D         Format it for the JSON object x000D      var item          title          foregrounds        foregrounds      backgrounds        backgrounds         x000D   x000D         THE PROBLEM SEEMS TO BE HERE   x000D         Error   Result of expression  library push   undefined  is not a function  x000D      library push item   x000D   x000D         Save to Database  Then on callback    x000D      console log  Added   lt b gt     title     lt  b gt     x000D      x000D    x000D   x000D  save    x000D   lt script src  https   cdn jsdelivr net npm lodash 4 17 10 lodash min js  gt  lt  script gt  x000D   x000D   x000D

[javascript] Nested JSON: How to add (push) new items to an object?

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