In the previous post, I talked about the meaning of various property attributes. Now let's see how we can define properties with desired attributes.

The Object.defineProperty and Object.defineProperties functions are somehow the opposites of Object.getOwnPropertydescriptor and Object.getOwnPropertydescriptors functions in that the outputs of the latter functions can be used as the input to the former functions.

In the following code snippet, the syntax of Object.defineProperty is illustrated:

    let ali = {};
    
    Object.defineProperty(ali, "age", {
        value: 19,
        writable: true,
        enumerable: true,
        configurable: true,
    });
    
    Object.defineProperty(ali, "name", {
        get: function () {
            if (typeof this._name === "undefined") {
                this._name = "Ali";
            }
            return this._name;
        },
        set: function (name) {
            this._name = name;
        },
        enumerable: true,
        configurable: true,
    });
    

Or, you can define all properties at once using Object.defineProperties, like this:

    let ali = {};
    
    Object.defineProperties(ali, {
        age: {
            value: 19,
            writable: true,
            enumerable: true,
            configurable: true,
        },
        name: {
            get: function () {
                if (typeof this._name === "undefined") {
                    this._name = "Ali";
                }
                return this._name;
            },
            set: function (name) {
                this._name = name;
            },
            enumerable: true,
            configurable: true
        },
    });

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Related Posts

• Object Creation and Manipulation Functions in JavaScript
• Property Descriptors in JavaScript
• Getting and Setting Property Descriptors in JavaScript (Part 1)
• Getting and Setting Property Descriptors in JavaScript (Part 2)