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JavaScript object methods list

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JavaScript object methods are used to manipulate and access properties of JavaScript objects in various ways. This is a list of common JavaScript object methods, including descriptions and examples of their usage.

objectName.methodName()
  1. Object.keys() – returns an array of a given object’s enumerable property names.
  2. Object.values() – returns an array of a given object’s enumerable property values.
  3. Object entries() – returns an array of a given object’s enumerable property pairs in the form of [key, value].
  4. Object.assign() – copies the values of all enumerable own properties from one or more source objects to a target object.
  5. Object.freeze() – freezes an object: other code can’t delete or change any properties.
  6. Object.seal() – seals an object, preventing new properties from being added and marking all existing properties as non-configurable.
  7. Object.create() – creates a new object with the specified prototype object and properties.
  8. Object.defineProperty() – adds a new property or modifies an existing property on an object, and specifies if the property can be changed or deleted.
  9. Object.hasOwnProperty() – returns a boolean indicating whether the object has the specified property as its property (not inherited).
  10. Object.is() – determines whether two values are the same value, and returns true or false.

Note: there are many more methods available on specific objects, such as Array or String.

JavaScript object methods list examples

Simple example code of some common JavaScript object methods.

<!DOCTYPE html>
<html>
<body>
    <script>
        // Object.keys()
        const myObj = {a: 1, b: 2, c: 3};
        const keysArray = Object.keys(myObj);
        console.log(keysArray);


        // Object.values()
        const myObj = {a: 1, b: 2, c: 3};
        const valuesArray = Object.values(myObj);
        console.log(valuesArray); // Output: [1, 2, 3]


        // Object.entries()
        const myObj = {a: 1, b: 2, c: 3};
        const entriesArray = Object.entries(myObj);
        console.log(entriesArray);


        // Object.assign()
        const obj1 = {a: 1, b: 2};
        const obj2 = {c: 3, d: 4};
        const newObj = Object.assign({}, obj1, obj2);
        console.log(newObj);

        // Object.freeze()
        const myObj = {a: 1, b: 2, c: 3};
        Object.freeze(myObj);
        myObj.a = 5;
        console.log(myObj);

        // Object.seal()
        const myObj = {a: 1, b: 2, c: 3};
        Object.seal(myObj);
        myObj.d = 4; // This will have no effect
        delete myObj.a; // This will have no effect
        console.log(myObj);

        // Object.create()
        const myObj = Object.create({a: 1, b: 2});
        myObj.c = 3;
        console.log(myObj.a); // 1
        console.log(myObj.b); // 2
        console.log(myObj.c); // 3

        // Object.defineProperty()
        const myObj = {};
        Object.defineProperty(myObj, 'a', {
            value: 1,
            writable: false
        });
        myObj.a = 2; // This will have no effect
        console.log(myObj.a); 

        // Object.hasOwnProperty()
        const myObj = {a: 1, b: 2};
        console.log(myObj.hasOwnProperty('a'));
        console.log(myObj.hasOwnProperty('c'));

        // Object.is()
        console.log(Object.is(1, '1')); // false
        console.log(Object.is(1, 1)); // true
        console.log(Object.is(-0, 0)); // false
        console.log(Object.is(NaN, NaN)); // true (weird, right?)

    </script>
</body>
</html>

Output:

JavaScript object methods list

Do comment if you have any doubts or suggestions on this JS object topic.

Note: The All JS Examples codes are tested on the Firefox browser and the Chrome browser.

OS: Windows 10

Code: HTML 5 Version

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