In the [previous post](https://steemit.com/javascript/@ghasemkiani/getting-and-setting-property-descriptors-in-javascript-part-2), 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:

```javascript
	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:

```javascript
	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
		},
	});
```

---

## Related Posts

* [Object Creation and Manipulation Functions in JavaScript](https://steemit.com/javascript/@ghasemkiani/object-creation-and-manipulation-functions-in-javascript)
* [Property Descriptors in JavaScript](https://steemit.com/javascript/@ghasemkiani/property-descriptors-in-javascript)
* [Getting and Setting Property Descriptors in JavaScript (Part 1)](https://steemit.com/javascript/@ghasemkiani/getting-and-setting-property-descriptors-in-javascript-part-1)
* [Getting and Setting Property Descriptors in JavaScript (Part 2)](https://steemit.com/javascript/@ghasemkiani/getting-and-setting-property-descriptors-in-javascript-part-2)