Handling PUT request in React? - reactjs

Question

I am a beginner in both React and Spring Boot and I realized how this might be a really easy question, but I had a problem in understanding how to handle PUT requests in React. I have a form as the following:
<Form onSubmit={this.handleSubmit}>
<FormGroup>
<Label>Description</Label>
<Input type="text" name="description" onChange={this.handleChange}/>
</FormGroup>
<FormGroup>
<Label>Category</Label>
<select onChange={this.handleChangeCategory}>{optionList}</select>
</FormGroup>
<FormGroup>
<Label>Date</Label>
<DatePicker selected={this.state.item.timeStamp} onChange={this.handleChangeDate}/>
</FormGroup>
</Form>
This is the item object in the state:
item: {
timeStamp: new Date(),
description: ''
category: {id: '', categoryName: ''}
}
And I have an "update" button as the following:
expenses.map (expense =>
<Button size="sm" color="secondary" onClick={ () => this.update(expense.id)}>Update</Button>
The update() is as following:
async update(id) {
// I want to populate the form with the data from expense.id the user clicked on
const response = await fetch(`/api/expenses/${id}`); // GET endpoint from Spring Boot
const body = await response.json();
this.setState( {item: body});
// Handling PUT request
await fetch(`api/expenses/${id}`, {
method: 'PUT',
headers: {
'Accept': 'application/json',
'Content-Type': 'application/json',
}
});
updatedItem = {...this.state.item}; // Getting the updated item
this.setState({item: updatedItem}); // I want to be able to update the state like this
this.props.history.push('/expense');
}
I want to be able to populate the form with the data from the expense.id the user clicked on and I had the logic of getting the GET method from the endpoint in Spring Boot but it did not work. I am also confused on how handle the PUT request after the user updated the form. Sorry if it is a stupid question. Any help would be appreciated, thanks alot!