React Select Dropdown onChange Event Handler Tutorial
Tags: react, abotwrotethis
Published: 2023-04-11 17:02:02

Do you want to learn how to handle the `onChange` event in a React Select dropdown? In this tutorial, we will guide you through step by step on how to use this event handler to manipulate the behavior of your select dropdown component. Let's get started!

## What is the `onChange` event in React?

In React, the `onChange` event is the event that gets triggered when the value of a form input element changes. This means that when a user selects a different option in a dropdown box, the `onChange` event will be fired.

## How to set up a React Select dropdown with `onChange` handler

Firstly, let's install the `react-select` package using the following command:

```
npm install react-select
```

Once we have the package installed, we can import it into our component:

```javascript
import React from 'react';
import Select from 'react-select';
```

Now we're ready to create our Select dropdown component:

```javascript
class SelectDropdown extends React.Component {
  state = {
    value: ''
  }

  handleChange = (selectedOption) => {
    this.setState({ value: selectedOption });
  }

  render() {
    return (
      <Select
        value={this.state.value}
        onChange={this.handleChange}
        options={options}
      />
    );
  }
}

export default SelectDropdown;
```

In the code above, we define our `SelectDropdown` class component. Inside the component, we define the state and set the initial value of the dropdown to an empty string. We also define the `handleChange` function which will be called when an option in the dropdown is selected.

In the `render` function, we define our `Select` component and pass in the `value` and `onChange` props. The `options` prop is the array of options to be rendered in the dropdown, which we will define next.

```javascript
const options = [
  { value: 'apple', label: 'Apple' },
  { value: 'banana', label: 'Banana' },
  { value: 'cherry', label: 'Cherry' }
];
```

We create an array of objects with a `value` and `label` property. The `value` property represents the actual value of the option, and the `label` property represents the display value of the option.

And that's it! We've created a fully functional Select dropdown with a `handleChange` event handler.

## What can we do with the `onChange` event handler?

The `onChange` handler function can be used to manipulate the behavior of the Select dropdown component. For example, we can use it to update the state of our component in real-time.

```javascript
class SelectDropdown extends React.Component {
  state = {
    value: ''
  }

  handleChange = (selectedOption) => {
    this.setState({ value: selectedOption });
    console.log(`Selected: ${selectedOption.value}`);
  }

  render() {
    return (
      <Select
        value={this.state.value}
        onChange={this.handleChange}
        options={options}
      />
    );
  }
}
```

In the code above, we've added a `console.log` statement to print out the selected option value to the console. This is just a basic example of what you can do with the `onChange` handler function. You can customize the function to fit your specific use case.

## Conclusion

In this tutorial, we've learned how to set up a React Select dropdown component and how to handle the `onChange` event. We've also demonstrated how the `onChange` handler function can be used to manipulate the behavior of the component. I hope this tutorial was helpful to you, and happy coding!