Recursively transform a JSON object to an array of key/value in JavaScript

Question

How to turn a JSON To a properties array in JS, no matter what's the JSON's depth ?

JSON

{
    "foo": {
        "bar": {
            "baz": "UP"
        }
    }
}

key/value properties

{
  "foo.bar.baz": "UP"
}

One-level solution

My current code only treats one level, instead of n:

var user = {name: 'Corbin', age: 20, location: 'USA'},
    key;

for (key in user) {
    if (user.hasOwnProperty(key)) {
        console.log(key + " = " + user[key]);
    }
}

Thank you :D

Please post your existing code and explain what is wrong with it. — Reinstate Monica Cellio
– Reinstate Monica Cellio, Commented Nov 7, 2016 at 10:14
Thank you @Archer, I've updated my question as you suggested it to me. My current solution doesn't cover any JSON depth, that's my problem. — Pleymor
– Pleymor, Commented Nov 7, 2016 at 10:39

georg · Accepted Answer · 2016-11-07 10:40:07Z

4

Basically, if a member is an object, make a recursive call, otherwise, update the output object:

data = {
    foo: "hello",
    bar: {
        baz: {
            qux: "UP"
        },
        spam: 'ham'
    }
}



function unwrap(obj, prefix) {

    var res = {};

    for (var k of Object.keys(obj)) {
        var val = obj[k],
            key = prefix ? prefix + '.' + k : k;

        if (typeof val === 'object')
            Object.assign(res, unwrap(val, key)); // <-- recursion
        else
            res[key] = val;
    }

    return res;
}

console.log(unwrap(data))

answered Nov 7, 2016 at 10:40

georg

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