Object.getOwnPropertyDescriptor()

Why Object.getOwnPropertyDescriptor ?

Object.getOwnPropertyDescriptor () returns a property identifier for the specified property of the specified object. This method allows examination of the precise definition of a property. A property in JavaScript consists of a name in the string value or a Symbol and property identifier. More information about property identifier types and attributes can be found in Object.defineProperty ().
Note that this is not a method to call on an object: it is a public function and you must pass it on to an object.

Syntax:

Object.getOwnPropertyDescriptor( obj , name )

• obj: The object that is to have its property attributes queried.
• name: The name of the property (or index of the array element) to query.

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A property descriptor is an ordinary JavaScript object that describes the attributes of a property. There are two kinds of JavaScript properties. A data property has a value and three attributes: enumerable, writable, and configurable. An accessor property has a getter and/or a setter method as well as enumerable and configurable attributes.

• value: The value for the property.
• writable: if true and only if the associated value can be changed.
• receive: A function that functions as a recipient for the property or that is undefined if a recipient does not.
• set: By default, undefined. It acts as a tuner for the property.
• enumerable: If true and only if this property occurs during enumeration of properties on the corresponding object.

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JavaScript Object.getOwnPropertyDescriptor() Examples

Example 1

        let obj = {
            website: "truecodes.org"
        };

        let arr = Object.getOwnPropertyDescriptor(obj,"website")

        console.log(arr.configurable);
        console.log(arr.value)

output:

true
truecodes.org

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Example 2

        let obj = {
            number: 10
        }
        let arr = Object.getOwnPropertyDescriptor(obj, 'number');
        console.log(arr.configurable);
        console.log(arr.enumerable);
        console.log(arr.value);

output:

true
true
10

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Example 3

        let obj = {
            foo: "true",
            get name() { return "codes" },
        };
        console.log(Object.getOwnPropertyDescriptors(obj))

output:

configurable: true
enumerable: true
value: “true”
writable: true

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Example 4

        let myObject, arr;

        myObject = { get foo() { return 17; } };
        arr = Object.getOwnPropertyDescriptor(myObject, 'foo');

        console.log(arr)

output:

configurable: true
enumerable: true
get: ƒ foo()
set: undefined

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Example 5

For this example, you need to know the “object” topics:

• Object.getOwnPropertyDescriptor()
• Object.prototype.hasOwnProperty()
• Object.values

javascript object example

<input type="text" id="username" />
    <input type="text" id="password" />
    <button onclick="login();">LOGİN</button>


    <script>


        function login() {
            var users = {
                "alex": 123,
                "rick": 234,
            };
            let username = document.getElementById("username").value,
                password = document.getElementById("password").value;

            if (users.hasOwnProperty(username) == true) {
                let arr1 = Object.getOwnPropertyDescriptor(users, "alex");
                let arr2 = Object.getOwnPropertyDescriptor(users, "rick");

                if (arr1.value == password) {
                    alert("welcome " + username);
                } else if (arr2.value == password) {
                    alert("welcome " + username);
                }else {
                    alert("You are entering the password incorrectly.")
        }
            } else {
                alet("You are entering the username incorrectly.")
            }
        }
    

    </script>

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Resources:

• https://developer.mozilla.org/
• https://www.javatpoint.com
• http://2ality.com/2016/0

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Browser Support

Chrome	5
Edge	yes
Firefox	4
Internet Explorer	9
Opera	11.6
Safari	5
Android webview	yes
Chrome for Android	yes
Edge mobile	yes
Firefox for Android	4
Opera Android	11.5