Question

I want to store an array of key value items, a common way to do this could be something like:

// the JSON data may store several data types, not just key value lists,
// but, must be able to identify some data as a key value list

// --> more "common" way to store a key value array
{
  [
    {"key": "slide0001.html", "value": "Looking Ahead"},
    {"key": "slide0008.html", "value": "Forecast"},
    {"key": "slide0021.html", "value": "Summary"},
    // another THOUSANDS KEY VALUE PAIRS
    // ...
  ],
  "otherdata" : { "one": "1", "two": "2", "three": "3" }
}

But, when there is many pairs / items, the string length becomes prohibited,
and I want a compact way, this could be an example:

// --> (1) a "compact" way to store a key value array
{    
  [
      {"slide0001.html", "Looking Ahead"},
      {"slide0008.html", "Forecast"},
      {"slide0021.html", "Summary"},
      // another THOUSANDS KEY VALUE PAIRS
      // ...
  ],
  "otherdata" : { "one": "1", "two": "2", "three": "3" }
}

Additionally, I want a way to identify the data as a keyvalue array,
because, I may want to store other data in the same JSON file.
I have these examples:

// --> (2) a "compact" way to store a key value array    
{
    "keyvaluelist":
    [
      {"slide0001.html", "Looking Ahead"},
      {"slide0008.html", "Forecast"},
      {"slide0021.html", "Summary"},
      // another THOUSANDS KEY VALUE PAIRS
      // ...
    ],
    "otherdata" : { "one": "1", "two": "2", "three": "3" }
}

// --> (3) a "compact" way to store a key value array    
{
    "mylist":
    {
      "type": "keyvaluearray",
  "data":
    [
        {"slide0001.html", "Looking Ahead"},
        {"slide0008.html", "Forecast"},
        {"slide0021.html", "Summary"},
                    // another THOUSANDS KEY VALUE PAIRS
                    // ...
    ]
    },
    "otherdata" : { "one": "1", "two": "2", "three": "3" }
}

What do you thing, which one do you suggest, do you have another way ?
Thanks.

UPDATE 1: Remove invalid code. Javascript => JSON

UPDATE 2: Add non key value data

UPDATE 3: Replace “[” and “]” for “{” and “}” in each key value pair

Answer 1

If the logic parsing this knows that {"key": "slide0001.html", "value": "Looking Ahead"} is a key/value pair, then you could transform it in an array and hold a few constants specifying which index maps to which key.

For example:

var data = ["slide0001.html", "Looking Ahead"];

var C_KEY = 0;
var C_VALUE = 1;

var value = data[C_VALUE];

So, now, your data can be:

[
    ["slide0001.html", "Looking Ahead"],
    ["slide0008.html", "Forecast"],
    ["slide0021.html", "Summary"]
]

If your parsing logic doesn’t know ahead of time about the structure of the data, you can add some metadata to describe it. For example:

{ meta: { keys: [ "key", "value" ] },
  data: [
    ["slide0001.html", "Looking Ahead"],
    ["slide0008.html", "Forecast"],
    ["slide0021.html", "Summary"]
  ]
}

… which would then be handled by the parser.