How can I find an object in Javascript

Question

I use a GUI to create my page, it is saved as a JSON file, then the JSON file is read by a CMS.

The problem: I would like to tinker with the objects I created, but the code is super minimized, an I cannot find the object.

To be clear with an example. I create a page with a button named "BUTTON". It exports in a JSON like this:

"S":[  
     {  
        "Y":"h",
        "b":1,
        "nm":"BUTTON1",
        "f":"1,0,1,0",
        "c":"FFFFFF,000000",
        "l":"2020,1840,4140,8820",
        "n":"Helvetica",
        "h":192,
        "L":0,
        "i":0,
        "j":1,
        "vj":1,
        "t":"Button",
        "Act":[  
           {  
              "e":"OnClick",
              "s":"\r\ngraphicReplace(\"Public/essai/vue0\");"
           }
        ]
     }
 ]

And it displays a button in the CMS. But, if I try something like "alert(S.t);", I get a "ReferenceError: S is not defined".

What I would like to do, is find a way to say: Find me the object, for which one of the properties is equal to "Button". Give me is name.

So that I can, using JS, change its position, size, and so on.

Full JSON

{  
   "PG":{  
  "v":5,
  "h":20480,
  "w":25600,
  "pc":"FFFFFF",
  "de":"",
  "st":0,
  "Act":[  

  ],
  "S":[  
     {  
        "Y":"h",
        "b":1,
        "nm":"BUTTON1",
        "f":"1,0,1,0",
        "c":"FFFFFF,000000",
        "l":"2020,1840,4140,8820",
        "n":"Helvetica",
        "h":192,
        "L":0,
        "i":0,
        "j":1,
        "vj":1,
        "t":"Button",
        "Act":[  
           {  
              "e":"OnClick",
              "s":"\r\ngraphicReplace(\"Public/essai/vue0\");"
           }
        ]
     }
  ]

} }

It looks like it's S[0].t.

Scimonster
– Scimonster

2015-06-10 11:20:03 +00:00
Commented Jun 10, 2015 at 11:20 — Scimonster
– Scimonster, Commented Jun 10, 2015 at 11:20

nicholaswmin · Accepted Answer · 2015-06-10 11:49:47Z

1

Your JSON holds an array which in turn contains the rest of the keys. You can see that after the 'S' key, brackets [] follow indicating just that.

So you(probably) need to use ..S[0].t

You can access arrays by their index like so [0] and keys with their 'names', like so '.Act'.

From what I see up there it should be json.PG.S[0].t where json means the name of the variable that actually contains that JSON,

var json = {
  "PG": {
    "v": 5,
    "h": 20480,
    "w": 25600,
    "pc": "FFFFFF",
    "de": "",
    "st": 0,
    "Act": [

    ],
    "S": [{
      "Y": "h",
      "b": 1,
      "nm": "BUTTON1",
      "f": "1,0,1,0",
      "c": "FFFFFF,000000",
      "l": "2020,1840,4140,8820",
      "n": "Helvetica",
      "h": 192,
      "L": 0,
      "i": 0,
      "j": 1,
      "vj": 1,
      "t": "Button",
      "Act": [{
        "e": "OnClick",
        "s": "\r\ngraphicReplace(\"Public/essai/vue0\");"
      }]
    }]
  }
}


alert(json.PG.S[0].t);

e.g assuming:

var json = {  
   "PG":{  
  "v":5,
  "h":20480,
  "w":25600,
  "pc":"FFFFFF",
  "de":"",
  "st":0,
  "Act":[  

  ],
  "S":[  
     {  
        "Y":"h",
        "b":1,
        "nm":"BUTTON1",
        "f":"1,0,1,0",
        "c":"FFFFFF,000000",
        "l":"2020,1840,4140,8820",
        "n":"Helvetica",
        "h":192,
        "L":0,
        "i":0,
        "j":1,
        "vj":1,
        "t":"Button",
        "Act":[  
           {  
              "e":"OnClick",
              "s":"\r\ngraphicReplace(\"Public/essai/vue0\");"
           }
        ]
     }
  ]
} }

edited Jun 10, 2015 at 11:49

answered Jun 10, 2015 at 11:20

nicholaswmin

23.2k16 gold badges103 silver badges175 bronze badges

Sign up to request clarification or add additional context in comments.

8 Comments

Pavlo Over a year ago

It's correct, but doesn't seem to be the case. S is not defined anyway.

Maxime Over a year ago

Thank you for your help. Indeed, I have tried this, and the result is inconclusive alert(S[0].t) VM2035:2 Uncaught ReferenceError: S is not defined

nicholaswmin Over a year ago

that's because you posted an incomplete JSON to begin with

Maxime Over a year ago

I did not think it was necessary to have the whole thing. I'll edit my first post to attach it all.

Maxime Over a year ago

Thanks for your detailed answer. Unfortunately, I do not know the name of the JSON variable, with turns my original question in "How can I find the json variable name?"

|

ozil · Accepted Answer · 2015-06-10 11:33:16Z

0

you Json should be like

var S = [
     {
         "Y": "h",
         "b": 1,
         "nm": "BUTTON1",
         "f": "1,0,1,0",
         "c": "FFFFFF,000000",
         "l": "2020,1840,4140,8820",
         "n": "Helvetica",
         "h": 192,
         "L": 0,
         "i": 0,
         "j": 1,
         "vj": 1,
         "t": "Button",
         "Act": [
            {
                "e": "OnClick",
                "s": "\r\ngraphicReplace(\"Public/essai/vue0\");"
            }
         ]
     }
]

or

var obj = {
    "S": [
         {
             "Y": "h",
             "b": 1,
             "nm": "BUTTON1",
             "f": "1,0,1,0",
             "c": "FFFFFF,000000",
             "l": "2020,1840,4140,8820",
             "n": "Helvetica",
             "h": 192,
             "L": 0,
             "i": 0,
             "j": 1,
             "vj": 1,
             "t": "Button",
             "Act": [
                {
                    "e": "OnClick",
                    "s": "\r\ngraphicReplace(\"Public/essai/vue0\");"
                }
             ]
         }
    ]
}  
alert(S[0].t);  // if you choose first
alert(obj.S[0].t);  // if you choose second

answered Jun 10, 2015 at 11:33

ozil

7,1639 gold badges38 silver badges62 bronze badges

5 Comments

nicholaswmin Over a year ago

It's being returned like that by a CMS - I think he has trouble assigning it to a variable or something like that

Maxime Over a year ago

Unfortunately, I do not make the JSON. It is created by the GUI, and read by the CMS. The very first character of it is a {, without any notion of variable :(

nicholaswmin Over a year ago

@MaximeVisconte did you actually JSON.parse()'d it first? - You have to parse it and assign it to a variable to access it properly

ozil Over a year ago

@Maxime Visconte assign it to some variable say var obj now alert(obj.S[0].t)

Maxime Over a year ago

I assume the CMS does it, since the object described in the document is displayed on the screen. Is that a bad assumption?

Collectives™ on Stack Overflow

How can I find an object in Javascript

2 Answers 2

8 Comments

5 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

8 Comments

5 Comments

Your Answer

Sign up or log in

Post as a guest

Related