Скачать или смотреть How to Create a Conditional Dropdown Using react-select in React

Learn how to create a conditional dropdown in React using the `react-select` library, and resolve common issues with value selection.
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How to Create a Conditional Dropdown Using react-select in React

When developing applications with React, sometimes you need to create dropdown menus that depend on one another — commonly known as conditional dropdowns. For example, when a user selects a genre from the first dropdown, the second dropdown needs to be populated with relevant books based on that genre. In this guide, we will walk you through how to achieve this using the react-select library.

The Problem

Imagine you want to include two dropdowns in your application:

Genre - The type of book a user is interested in.

Books - A list of books that corresponds to the genre selected.

Your goal is for the Books dropdown to display options based on the genre that the user chooses. However, you notice that while the dropdown does filter correctly, the selected value does not appear in the dropdown. This is a common issue that developers face when dealing with controlled components in React, especially when using libraries like react-select.

The Solution

Let’s walk through how to set up these conditional dropdowns correctly. Here's a step-by-step breakdown of the solution:

Step 1: Create the Component

First, ensure you have the base structure for your React component. You will need a constructor to hold the state and methods to handle changes in the dropdowns.

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Step 2: Define Your Options

Next, create the arrays that will hold your genres and books. Make sure to define the relationship between genres and books through a link key.

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Step 3: Filter the Book Options

In your render method, filter the books based on the selected genre. This ensures that the second dropdown shows only the relevant books depending on what is selected in the first dropdown.

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Step 4: Render the Select Components

Finally, render both the dropdowns, ensuring to pass the entire selectedOption state (not just .value) to the value prop of each Select component.

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Complete Code Example

Here’s how the complete component looks:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

With this setup, you now have a functioning conditional dropdown in your React application using react-select. If you encounter issues where no value appears in the select bar, remember to pass the whole selected option object instead of just its value. Enjoy building your dynamic forms with ease!