How to handle user input in React.js forms?

@cali_green 

In React.js, you can handle user input in forms using controlled components. Controlled components are form elements whose values are controlled by React. Here's how you can handle user input in React.js forms using controlled components:

1. Create a state variable to store the value of the form input. In your component's state, initialize the variable with an empty string or the initial value of the input.

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state = {
  inputValue: ''
};

1. Bind the input value to the state variable using the value prop. This makes the React state the source of truth for the input's value.

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<input type="text" value={this.state.inputValue} onChange={this.handleChange} />

1. Implement the handleChange method to update the state variable whenever the user types into the input.

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handleChange = (event) => {
  this.setState({ inputValue: event.target.value });
};

1. Handle the form submission by preventing the default behavior of the form, and then process the input value stored in the state variable as desired.

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handleSubmit = (event) => {
  event.preventDefault();
  // Process the form input (e.g., submit it to a server, perform calculations, etc.)
};

1. Add an event listener to listen for the form submission and call the handleSubmit method.

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<form onSubmit={this.handleSubmit}>
  {/* ...form fields */}
  <button type="submit">Submit</button>
</form>

By using the above approach, you can easily handle user input in React.js forms and manage the state of the form.