How to get a subset of a javascript object's properties?

Last Updated : 21 Nov, 2021

To get the subset of properties of a JavaScript Object, we make use of destructuring and Property Shorthand. The destructuring assignment syntax is a JavaScript expression that makes it possible to unpack values from arrays, or properties from objects, into distinct variables.
Syntax:

subset = (({a, c}) => ({a, c}))(obj);

Example1: Get subset of a javascript object's properties using destructuring assignment.

html

<!DOCTYPE html>
<html>

<head>
    <title>
      Get a subset of a javascript object’s properties
  </title>
</head>

<body>
    <center>
        <h1 style="color:green">
          GeeksforGeeks
      </h1>
        <h2>
          Get a subset of a javascript object’s properties
      </h2>
        <script>
            obj = {
                property1: 5,
                property2: 6,
                property3: 7
            };
            subset = (({
                property1, property3
            }) => ({
                property1, property3
            }))(obj);

            var output = 'Subset Object: <br>';
            for (var property in subset) {
                output += property + ': ' + subset[property] + ';<br>';
            }
            document.write(output);
        </script>
    </center>
</body>

</html>

Output:

In ES6 there is a very concise way to do this using destructing. Destructing allows you to easily add on to objects and make subset objects.
Syntax:

const {c, d, ...partialObject} = object;
const subset = {c, d};

Example 2: Get subset of a javascript object's properties using destructuring assignment.

html

<!DOCTYPE html>
<html>

<head>
    <title>
      Get a subset of a javascript object’s properties
  </title>
</head>

<body>
    <center>
        <h1 style="color:green">
          GeeksforGeeks
      </h1>
        <h2>
          Get a subset of a javascript object’s properties
      </h2>
        <script>
            const object = {
                property1: 'a',
                property2: 'b',
                property3: 'c',
                property4: 'd',
            }

            const {
                property1,
                property4,
                ...pObject
            }

            = object;
            const subset = {
                property1,
                property4
            }

            ;
            var output = 'Subset Object: <br>';
            for (var property in subset) {
                output += property + ': ' +
                    subset[property] + ';<br>';
            }

            document.write(output);
        </script>
    </center>
</body>

</html>