Working with the Reflect API in JavaScript
Tags: javascript, reflect, api
Published: 2023-04-09 12:28:14

by [Solomon Jude](https://blog.openreplay.com/authors/solomon-jude)

If you are reading this article, the question in your mind is probably, "What does this `Reflect` API do?"

In this article, we will understand the concept of `Reflect` in JavaScript, and discover some of the methods available in the `Reflect` API and how they can be used to improve your code in real-world scenarios.

Whether you are a beginner or an experienced developer, this article will provide a clear guide to working with the `Reflect` API and help you take your JavaScript skills to the next level.


## Definition of JavaScript `Reflect` API

The `Reflect` API in JavaScript is an inbuilt ES6 global object that allows you to perform various tasks related to interacting with and manipulating JavaScript objects, such as setting and getting property values, creating and defining new objects, and more.

Think of the JavaScript `Reflect` API as a toolbox with different tools (**methods**) that helps you understand and control JavaScript objects. The `Reflect` API helps us open the box (object), look inside, and even change what is inside. It also helps us figure out information about the box (object), like how many things are inside and what kind of box it is.

The `Reflect` API is particularly useful in modern JavaScript development. It makes your code easier to read and understand, which is important when working on large or complex projects. It can also help you avoid mistakes.


## How to use the `reflect` API

The `Reflect` API is built into JavaScript, so you don't need to `import` or `install` any library in your code for the `Reflect` API to work if it's already supported in your JavaScript environment. The `Reflect` API is part of the JavaScript language itself and is available in modern JavaScript environments, such as modern browsers and recent versions of **Node.js**. To use the `Reflect` API, simply call the desired method, such as  `Reflect.get()`, `Reflect.set()`, etc.

Here is an example of how you might use the `Reflect` API in your code if it's already supported:

```javascript
// file: index.js
let obj = {name: 'Solomon', class: 2}
let value = Reflect.get(obj, 'name')
console.log(value) 



// in terminal
$ node index.js
Solomon  //this is the result of the above code
```

The image below this text provides a pictorial view of what the information discussed looks like on my computer.

![1](https://blog.openreplay.com/images/working-with-the-reflect-api-in-javascript/images/Qaw6WLs.jpg)



Here is the result at the terminal


![2](https://blog.openreplay.com/images/working-with-the-reflect-api-in-javascript/images/HvF06d5.jpg)



In this example, the `Reflect` API is used directly, without any additional setup or imports. If your version of **Node.js** supports the `Reflect` API, this code should work without any issues. Therefore, you must have `Node.js` installed on your computer.





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## Commonly used `Reflect` API

These are the most commonly used methods in the API.

### `Reflect.get()` 

The `Reflect.get()` method allows you to get the value of an object's property. Think of it like a tool that helps you get a specific item from a box. Here's how it works with an example:


```javascript
// file: index.js
let person = { name: 'Solomon', class: 4};
let name = Reflect.get(person, 'name')
console.log(name); // Result: Solomon


// in terminal
$ node index.js
Solomon //Result
```
In this example, we have an object `person` with two properties, `name`, and `class`. We use `Reflect.get` method to get the value of the `name`. Then, we log the value of the `name` to the terminal, which is the output called `Solomon`.

**NOTE:** The approach of using the `Reflect.get(person, 'name')` is that this method will return a value **`undefined`** if the property is not found, which is useful for debugging.


Here is an example:


```javascript
// file: index.js
let person = { name: 'Solomon', class: 4};
let address = Reflect.get(person, 'address')
console.log(address); // Result: undefined


// in terminal
$ node index.js
undefined //Result
```

The `Reflect.get()` method works by taking in two arguments:
- `target`: The object to target.
-  `propertykey`: The name of the property you want to get.

This method has an optional third argument, the;

-  `receiver` (optional): This argument allows you to specify the object that should be treated as the `this` object when the property is accessed.



### `Reflect.set()` 

The `Reflect.set()` method allows you to change the value of a property in an object.

Here is an example of how you can use `Reflect.set()`:

```javascript
// file: index.js
let person = { name: 'Solomon'};
Reflect.set(person, 'name', 'Jude');
console.log(person.name) //Result: 'Jude'



// in terminal
$ node index.js
Jude // Result
```

In the example above, we first created an object called `person` with a property called `name` and the value `Solomon`. Then we used the Reflect.set() method to change the value of the `name` property to `Jude`. Finally, we logged the value of the `name` property and saw that it was successfully changed to `Jude`.

This method works by taking in three arguments:

- `target` : The object you want to set a property on.
- `propertykey` : The name of the property you want to set.
- `value` : The new value you want to set the property to.


This method also has an optional fourth argument, the;
    
- `receiver` (optional): This is the object that should be treated as the `this` object when the property is set.


### `Reflect.has()`

The `Reflect.has()` method is a way to check if an object has a certain property. It is like asking if an object has a specific thing. This method returns a **`Boolean`** (true or false) value.

Here is an example to help illustrate this concept:

```javascript
// file: index.js
let person = { name: 'Jude'};
let hasName = Reflect.has(person, 'name');
console.log(hasName);


// in terminal
$ node index.js
true //Result
```
In this example, the second line creates an object called `person` with a property `name`. The third line uses the `Reflect.has()` method to check if the `person` object has a property called `name`. The result of this check is stored in a variable called `hasName`.

Finally, the fourth line logs the value of `hasName`, which is **`true`**, because the `person` object does have a property called `name`, and if the object does not have the property, it returns **`false`**

Here is an example:

```javascript
// file: index.js
let person = { age: 4};
let hasName = Reflect.has(person, 'name');
console.log(hasName);


// in terminal
$ node index.js
false //Result
```
This method takes two arguments:

- `target`: The object that you want to check for a property.
- `propertykey`: The name of the property that you want to check.

### `Reflect.defineProperty()`

The `Reflect.defineProperty()` method is a way to add or change a property on an object. It is like adding a new toy to a box of toys or changing the color of a toy in the box. This method works by taking in three arguments:

- `target`: The object on which the property is to be defined or modified.
- `propertykey`: The property's name to define or modify.
- `attributes`: The attribute of the property being defined.


Here is an example to help illustrate this concept:

```javascript
//This is an example of how to use Reflect.defineProperty() method to define a new property on an object

let obj = {};
Reflect.defineProperty(obj, "name",{ value: "OpenReplay"});
console.log(obj.name);
//Result: "OpenReplay"



//This is an example of how to use Reflect.defineProperty() method to modify an existing property on an object

let obj = { name: "Solomon Jude"};
Reflect.defineProperty(obj, "name", { value: "Solomon Franklin"});
console.log(obj.name);
//Result: "Solomon Franklin"
```

### `Reflect.deleteProperty()`

The `Reflect.deleteProperty` method is a way to remove a property from an object. Imagine you have a toy box with toys in it, and you want to take one of the toys out. The `Reflect.deleteProperty()` method is like taking a toy out of the toy box.

Here is an example:

```javascript
// file: index.js
let toyBox = {
    car: 'red car',
    plane: 'blue plane',
    boat: 'yellow boat'
};

let success = Reflect.deleteProperty(toyBox, 'car');

if(success) {
    console.log('The car toy was removed successfully');
}else {
    console.log('failed to remove the car toy.');
}


// in terminal
$ node index.js
The car toy was removed successfully
```
In this example, we have an object called `toyBox` with three properties: `car`, `plane`, and `boat`. We use the `Reflect.deleteProperty()` method to remove the `car` property from the `toyBox` object.

This method takes in two arguments:

- `target`: The object from which you want to delete a property.
- `key`: the name of the property you want to delete.



## Conclusion

In this article, we learned that the Reflect API in JavaScript is a powerful tool for working with objects, providing a set of methods to perform a wide range of operations, such as

* `Reflect.get()` method to access the values of properties on an object.
* `Reflect.set()` method to set the value of the property on an object. 
* `Reflect.has()` method for checking if a specified property exists or not. 
* `Reflect.delete()` method to delete a specified property from an object.
* `Reflect.define()` method to define properties on an object
* `Reflect.getPrototype()` method to retrieve the prototype of an object.

These capabilities allow for more flexibility and control when manipulating objects in your code, resulting in more efficient code.



## Additional Resources

[Reflect - JavaScript | mdn](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Reflect)

[JavaScript Reflection and Reflect API](https://www.codeproject.com/Articles/5275933/JavaScript-Reflection-and-Reflect-API#preventExtensions)



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