Javascript JSON conversion

Question

I have a JSON like below (which is basically constructed out of a Dictionary):

{ "test1":["a","b","c"], "test2":["c","d"], "test3":["f"] }

And I want to parse and format above like this:

[
    {
        "user": "test1",
        "cmd": ["a","b","c"]      
    }
    {
        "user": "test2",
        "cmd": ["c","d"]
    },
    {
        "user": "test3",
        "cmd": ["f"]
    }
]

Any suggestions on how to do this using JavaScript?

**[What have you tried](http://mattgemmell.com/what-have-you-tried/)**? — Joseph Silber, Aug 11 '14 at 02:09
If you obtain a list of keys for this dictionary, then the solution will be straightforward: http://stackoverflow.com/questions/3068534/getting-javascript-object-key-list — Anderson Green, Aug 11 '14 at 02:17
[**There's no such thing as a "JSON Object"**](http://benalman.com/news/2010/03/theres-no-such-thing-as-a-json/)! — Joseph Silber, Aug 11 '14 at 02:23
@JosephSilber - [The JSON Object on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON) (JSON is actually an Object in JS) ps: I know what you meant. — Derek 朕會功夫, Aug 11 '14 at 02:42
@Derek朕會功夫 - Have you read that article I linked to? [Did you see this](http://i.imgur.com/u40ZA8H.png)? — Joseph Silber, Aug 11 '14 at 02:45
@JosephSilber - [But did you see this though?](http://imgur.com/wWi78pS) — Derek 朕會功夫, Aug 11 '14 at 02:47
@Derek朕會功夫 - Yes, but you were just repeating what the article I linked to already says. — Joseph Silber, Aug 11 '14 at 02:48

Joseph Silber · Accepted Answer · 2014-08-11T02:34:36.257

3

It's not clear from your question if your dictionary is a JS object or a JSON string. If it's JSON, you'll have to first parse it:

var dictionary = JSON.parse(theJSONstring);

then follow the instructions below.

If you're supporting IE8-, you'll have to polyfill JSON support.

var dictionary = {
    "test1": ["a","b","c"],
    "test2": ["c","d"],
    "test3": ["f"],
};

var commands = Object.keys(dictionary).map(function (key) {
    return { user: key, cmd: dictionary[key] };
});

If you're unfortunate enough that you have to support ancient browsers (IE8-), use this:

var dictionary = {
    "test1":["a","b","c"],
    "test2":["c","d"],
    "test3":["f"],
};

var commands = [];

for (var key in dictionary) {
    if (Object.prototype.hasOwnProperty.call(dictionary, key))
    {
        commands.push({ user: key, cmd: dictionary[key] });
    }
}

edited Aug 11 '14 at 02:34

answered Aug 11 '14 at 02:19

Joseph Silber

214,931
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Why not `if (dictionary.hasOwnProperty(key))`? – nnnnnn Aug 11 '14 at 02:28
@nnnnnn - Crockford reccomends it, in case someone was stupid enough to add their own `hasOwnProperty` somewhere in the prototype chain. – Joseph Silber Aug 11 '14 at 02:29
@nnnnnn - [Because `hasOwnProperty` could be overwrote by something else.](http://eloquentjavascript.net/1st_edition/chapter8.html#p2420ca9a47b21ef8) – Derek 朕會功夫 Aug 11 '14 at 02:35

Boyan Hristov · Answer 2 · 2014-08-11T02:27:11.313

0

Maybe something like this:

var testObject = {
    "test1": ["a", "b", "c"],
        "test2": ["c", "d"],
        "test3": ["f"]
},
userArray = [];

for (test in testObject) {

    if (Object.prototype.hasOwnProperty.call(testObject, test)) {

        userArray.push({
            user: test,
            cmd: testObject[test]
        });

    }
}

edited Aug 11 '14 at 02:27

answered Aug 11 '14 at 02:13

Boyan Hristov

1,067
3
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https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/for...in – jdphenix Aug 11 '14 at 02:17
Ok... what about my code? Works perfectly fine.... [here is a fiddle](http://jsfiddle.net/aq3a0htu/) – Boyan Hristov Aug 11 '14 at 02:19
@JosephSilber I'm confused: why do we need to use `hasOwnProperty` here? – Anderson Green Aug 11 '14 at 02:19
You did not fix your answer. You broke it. – Joseph Silber Aug 11 '14 at 02:25

Javascript JSON conversion

2 Answers2