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JavaScript React Components (2018) Managing State and Data Flow Managing State Review

Posted by Joshua Lucas
Joshua Lucas
8,778 Points

I believe the answer is incorrect?

Here is the question: 

Complete the code to bring in all student objects in the previous state into the students array in setState().

class Students extends Component {
  state = {
    students: [ // array of student objects ]
  };
  this.setState( prevState => ({
    students: [
      {ANSWER HERE},
      { // new student object }
    ]
  }));
  render() { ... }
}

this was my answer 

...this.state.students,

and it told me I was incorrect? Wouldn't you use the spread operator to bring in the students object? Please help.

1 Answer

Ignacio Rocha
Ignacio Rocha
7,462 Points
Ignacio Rocha
Ignacio Rocha
7,462 Points

You're quite right you need to use the spread operator but since you are inside the this.setState function you need to take the value from prevState not this.state, like so:

this.setState(prevState => ({
  students: [
       ...prevState.students
    ]
}));