Acording to the setState documentation the callback should fire after the new state has been set. However, my code

console.log(school);
this.setState({ lastSegment: school },console.log(this.state.lastSegment));

Prints:

Middle
Grammar

Since school="Middle" why is the setState callback printing "Grammar" (which is the previous value of this.state.lastSegment)

Acording to the setState documentation the callback should fire after the new state has been set. However, my code

console.log(school);
this.setState({ lastSegment: school },console.log(this.state.lastSegment));

Prints:

Middle
Grammar

Since school="Middle" why is the setState callback printing "Grammar" (which is the previous value of this.state.lastSegment)

• javascript
• react-native

1 Answer 1

The callback is a function passed to another function as an argument and sometimes referred as anonymous function which means a function without a name, so you're executing the console.log in place, and returning the value as the second argument to setState. You want to pass in a function, not the result of console.log.

this.setState({ lastSegment: school }, () => { 
  console.log(this.state.lastSegment); 
});

or using ES5 syntax:

this.setState({ lastSegment: school }, function() { 
  console.log(this.state.lastSegment); 
});