json notation in function calls

I’ve been using JSON to help move objects, arrays, etc. between the client and server.

Basically, JSON is a serialisation method, which allows an object to be compressed to a string description, sent, and decompressed on the far side.

For example, the following is a “Kae” object:

{
  name:          "Kae",
  surname:      "Verens",
  dependants:  [ "Bronwyn Verens", "Jareth Verens" ],
  age:            29
}

The above is easy to understand, and can be compressed by stripping the spaces:

{name:"Kae",surname:"Verens",dependants:["Bronwyn Verens","Jareth Verens"],age:29}

There are four types of variable in the above; numeric, string, array, and object.

When you call a function in JavaScript with the above, after receiving it from the server, you must first “eval” it into a usable state.

Assuming the received serialised string is called “ret”, the following should be all that’s needed, assuming the values are going to the function “call_me()”.

call_me(eval(ret));

The above will work for each of the following strings:

ret="name=\"Kae\"";
ret="[\"Bronwyn Verens\",\"Jareth Verens\"]";
ret="age=29";

But, this will not:

ret="{name:\"Kae\",surname:\"Verens\",dependants:[\"Bronwyn Verens\",\"Jareth Verens\"],age:29}";

The problem is that object notation ({ ... : ... }) fails. It took me a while to figure out why.

This is valid code:

var kae={name:"Kae",surname:"Verens",dependants:["Bronwyn Verens","Jareth Verens"],age:29};
call_me(kae);

But, the following is not:

call_me({name:"Kae",surname:"Verens",dependants:["Bronwyn Verens","Jareth Verens"],age:29});

Why? Who knows… Anyway – this works:

call_me(({name:"Kae",surname:"Verens",dependants:["Bronwyn Verens","Jareth Verens"],age:29}));

Remember, the original premise was that the JSON was to be eval’ed while the function call was being created, so this ends up as:

call_me(eval(ret.charAt(0)=='{'?'('+ret+')':ret));

Ugly, but it works.

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