React: 'selected' attribute not working with multiple <select> elements

2 min read 05-10-2024

React: 'selected' Attribute Not Working with Multiple `<select>` Elements

Let's face it, working with multiple <select> elements in React can be tricky. You might encounter situations where the selected attribute seemingly doesn't work as expected. This article explores this common issue and provides solutions to make your multiple selection forms function smoothly.

The Problem:

Imagine you have two <select> elements in your React component, both with the same options. You want to pre-select specific options for each select element, but the selected attribute doesn't seem to be doing its job.

Scenario:

import React from 'react';

const MyComponent = () => {
  return (
    <div>
      <select>
        <option value="apple" selected>Apple</option>
        <option value="banana">Banana</option>
        <option value="orange">Orange</option>
      </select>

      <select>
        <option value="apple">Apple</option>
        <option value="banana" selected>Banana</option>
        <option value="orange">Orange</option>
      </select>
    </div>
  );
};

export default MyComponent;

You might expect both selects to display the initially selected options ("Apple" and "Banana" respectively), but that's not always the case.

The Explanation:

The selected attribute in HTML works by comparing the value of the option with the value of the value attribute of the <select> element. However, since both <select> elements share the same options with identical values, the browser might pick the first instance of the selected value it finds.

The Solution:

To achieve the desired behavior, we need to ensure each <select> element has a unique identifier. There are multiple ways to achieve this:

Unique Keys:

This approach uses a unique key for each <select> element. React uses these keys for efficient rendering and updating.

import React from 'react';

const MyComponent = () => {
  return (
    <div>
      <select key="select1">
        <option value="apple" selected>Apple</option>
        <option value="banana">Banana</option>
        <option value="orange">Orange</option>
      </select>

      <select key="select2">
        <option value="apple">Apple</option>
        <option value="banana" selected>Banana</option>
        <option value="orange">Orange</option>
      </select>
    </div>
  );
};

export default MyComponent;

Unique Values:

Another way is to assign unique values to each <select> element, even if the displayed text is the same.

import React from 'react';

const MyComponent = () => {
  return (
    <div>
      <select>
        <option value="apple1" selected>Apple</option>
        <option value="banana1">Banana</option>
        <option value="orange1">Orange</option>
      </select>

      <select>
        <option value="apple2">Apple</option>
        <option value="banana2" selected>Banana</option>
        <option value="orange2">Orange</option>
      </select>
    </div>
  );
};

export default MyComponent;

State Management:

If you have more complex scenarios with dynamic selections, consider using state management. You can track the selected options in your component state and update the selected attribute based on the current state.

import React, { useState } from 'react';

const MyComponent = () => {
  const [selectedFruit1, setSelectedFruit1] = useState("apple");
  const [selectedFruit2, setSelectedFruit2] = useState("banana");

  return (
    <div>
      <select value={selectedFruit1} onChange={(e) => setSelectedFruit1(e.target.value)}>
        <option value="apple">Apple</option>
        <option value="banana">Banana</option>
        <option value="orange">Orange</option>
      </select>

      <select value={selectedFruit2} onChange={(e) => setSelectedFruit2(e.target.value)}>
        <option value="apple">Apple</option>
        <option value="banana">Banana</option>
        <option value="orange">Orange</option>
      </select>
    </div>
  );
};

export default MyComponent;

Conclusion:

The selected attribute in React can be a little tricky when dealing with multiple <select> elements, but with these simple solutions, you can ensure proper initial selections. Remember to choose the approach that best fits your specific needs and maintainability.

Additional Resources:

MDN Web Docs - <select> Element: https://developer.mozilla.org/en-US/docs/Web/HTML/Element/select
React Documentation - State and Lifecycle: https://reactjs.org/docs/state-and-lifecycle.html

React: 'selected' attribute not working with multiple <select> elements