How to swap key and value of JSON element using JavaScript ?

Given a JSON object and the task is to swap the JSON object key with values and vice-versa with the help of JavaScript. 

Approach 1:

• Create a new empty object.
• Visit every key of object by for loop and add the elements from old object to the new object in reverse form(by swapping the key and values).

Example: This example implements the above approach. 

html

<h1 style="color:green;">
    GeeksForGeeks
</h1>

<p id="GFG_UP1">
</p>

<p id="GFG_UP2">
</p>

<button onclick="GFG_Fun()">
    click here
</button>

<p id="GFG_DOWN">
</p>

<script>
    var up1 = document.getElementById('GFG_UP1');
    var up2 = document.getElementById('GFG_UP2');
    var down = document.getElementById('GFG_DOWN');

    var obj = {
        "Prop_1": "Val_1",
        "Prop_2": "Val_2",
        "Prop_3": "Val_3"
    };

    up1.innerHTML = "Click on the button to swap"
            + " the key with values.";

    up2.innerHTML = JSON.stringify(obj);

    function swapValues(j){
        var res = {};
        for(var key in j){
            res[j[key]] = key;
        }
        return res;
    }

    function GFG_Fun() {
        down.innerHTML =
            JSON.stringify(swapValues(obj));
    }
</script>

Output:

Swap key and value of JSON element using JavaScript

Approach 2:

• Create a new empty object.
• For each key of the object, add the elements from old object to the new object in reverse form (by swapping the key and values). Using .ForEach() method

Example: This example implements the above approach. 

html

<h1 style="color:green;">
    GeeksforGeeks
</h1>

<p id="GFG_UP1">
</p>

<p id="GFG_UP2">
</p>

<button onclick="GFG_Fun()">
    click here
</button>

<p id="GFG_DOWN">
</p>

<script>
    var up1 = document.getElementById('GFG_UP1');
    var up2 = document.getElementById('GFG_UP2');
    var down = document.getElementById('GFG_DOWN');

    var obj = {
        "Prop_1": "Val_1",
        "Prop_2": "Val_2",
        "Prop_3": "Val_3"
    };

    up1.innerHTML = "Click on the button to "
            + "swap the key with values.";

    up2.innerHTML = JSON.stringify(obj);

    function swapValues(o) {
        const res = {};

        Object.keys(o).forEach(key => {
            res[o[key]] = key;
        });
        return res;
    }

    function GFG_Fun() {
        down.innerHTML =
            JSON.stringify(swapValues(obj));
    }
</script>

Output:

Swap key and value of JSON element using JavaScript