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Use ref in React to get the value of an input field:

1. Set the ref attribute on the input element.
2. Access the value of an input field on a ref object, for example ref.current.value.

import {useRef} from 'react';

const App = () => {
  const inputRef = useRef(null);

  function handleClick() {
    console.log('value 👉️', inputRef.current.value);
  }

  return (
    <div>
      <input
        ref={inputRef}
        type="text"
        id="message"
        name="message"
      />

      <button onClick={handleClick}>Log message</button>
    </div>
  );
};

export default App;

This example shows how to get the value of an uncontrolled input field.

Note that inputs have no onChangeattributes or values ​​set.

We can use defaultValuethe attribute to pass an initial value to an uncontrolled input. However, this is not required and we can omit the attribute if we do not want to set an initial value.

When working with uncontrolled input fields, we use refto access the input.

useRef()The hook can be passed an initial value as an argument. The hook returns a mutable ref object whose .current property is initialized to the passed argument.

请注意, we have to access the current property of the ref object in order to access the input element on which we set the ref attribute.

When we pass a ref prop to an element, for example <input ref={myRef} />, React sets the properties of the ref object .currentto the corresponding DOM node.

The useRef hook creates a normal JavaScript object but gives us the same ref object on every render. In other words, it’s almost a memoized object value with a .current property.

It is important to note that when you change the value of the ref's current attribute, it will not cause a re-render.

Each time the user clicks the button in the example, the uncontrolled input value is recorded.

We should not set the value prop on uncontrolled inputs ( onChangeinput fields that don't have a handler) because this will make the input field immutable and you won't be able to input.