Create a Controlled Input passing setState a function

Tell us what’s happening:
Describe your issue in detail here.
Why does passing a function to the setState not work here? From the Use State to Toggle an Element lesson, I thought I could pass setState a function anywhere I need the most current values of the state and props. I am also confused by the difference between using value={this.state.input} vs passing the setState function I did below to update the state?

Thank you!

Your code so far

class ControlledInput extends React.Component {
constructor(props) {
  this.state = {
    input: ''
  // Change code below this line
  this.handleChange = this.handleChange.bind(this);
  // Change code above this line
// Change code below this line
    this.setState(state => ({input:}));
// Change code above this line
render() {
  return (
      { /* Change code below this line */}
      <input type="text" value={this.state.input} onChange={this.handleChange}/>
      { /* Change code above this line */}
      <h4>Controlled Input:</h4>
  **Your browser information:**

User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/98.0.4758.102 Safari/537.36

Challenge: Create a Controlled Input

Link to the challenge:

I also am confused about why passing the function doesn’t work- does it have to do with how works, or is it just because isn’t set in the initial state?

This is really interesting, I think this may have to do with how react works. If you put the

state => ({input:})

on a function like this

function updateInput (){
state => ({input:})

and the call it in the setState, it seems to work. Maybe it also has to do that React setState is asynchronous. I will like to know more about this as well…

This thread has an explanation.

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Why aren’t we using the current state?

Because the previous state (or props) isn’t used to derive the new state. The new state is just whatever is.

An example of a derived state update often given is a counter component where we take the previous state (and/or props) and add to it. Although simple counters usually work just fine without deriving the state.

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