Add object to array in JSON

Question

I am trying to add an object in an array to an item in a JSON object.

The result I am looking for is:

{ "AvailableFacets":[ "color", "sheenlevel" ], 
  "Selections":[ 
      { "Facet":"color", "Value":"red" }, 
      { "Facet":"color", "Value":"blue" } 
  ]
}

but I get the error "TypeError: myJsonObject.Selection.push is not a function" when doing the following:

var testJson = function () {
    var myJsonObject = $.parseJSON('{"AvailableFacets":["color", "sheenlevel"]}');
    myJsonObject.Selection = "[]";
    var newObject1 = $.parseJSON('{"Facet":"color", "Value":"red"}');
    var newObject2 = $.parseJSON('{"Facet":"color", "Value":"blue"}');
    myJsonObject.Selection.push(newObject1);

    return myJsonObject;
};

What am I doing wrong?

Why are you setting Selection to a string instead of an array? — Matt Ball
– Matt Ball, Commented Mar 26, 2013 at 0:49
myJsonObject.Selection = [];, but since you're testing JSON: myJsonObject.Selection = $.parseJSON('[]'); :p — Šime Vidas
– Šime Vidas, Commented Mar 26, 2013 at 0:51
Am I setting it to a string? I am new to this, thought that was an array. — Villem
– Villem, Commented Mar 26, 2013 at 0:51
"[]" is a string containing the two characters [ and ], while [] is an array literal containing zero items. — Guffa
– Guffa, Commented Mar 26, 2013 at 0:53

Jason Sperske · Accepted Answer · 2013-03-26 00:49:08Z

2

"[]" !== []. Did that help? You are using the wrong types. Also you are looking for an output with "Selections" but you are attempting to define "Selection", but I assume that is a typo. This should work:

myJsonObject.Selection = [{"Facet":"color", "Value":"red"},{"Facet":"color", "Value":"blue"}];

But if you wanted to parse a string of JSON as JSON then just change

myJsonObject.Selection = "[]";

to:

myJsonObject.Selection = [];

answered Mar 26, 2013 at 0:49

Jason Sperske

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5 Comments

Villem Over a year ago

You guys are beautiful! Both [] and $.parseJSON('[]') worked!

Villem Over a year ago

Thanks for pointing out the typo as well, had not seen that. :)

Villem Over a year ago

Do I need to use $.parseJSON all of those times, or is it overkill?

Jason Sperske Over a year ago

It's overkill. You should only use parseJSON when you are parsing a string (like from an AJAX request, or a textBox)

Villem Over a year ago

I kept the first $.parseJSON only, works fine without the rest. Thank you all very much, it's wonderful to get such quick replies, especially since it's two in the morning here in Sweden :S

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