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JavaScript React Basics (2018) Introducing Props Iterating and Rendering with map()

Posted by Heather Lau
Heather Lau
16,665 Points

Should I use constructor in react component or not?

I found that the tutorial simply define state inside the react component:

state = {
  score: 0
}

But I saw other online examples use constructor:

constructor(props) {
  super(props) 
  this.state = {
    score: 0
  }
}

I'm quite confused. Why they use constructor? For what cases I should use it?

1 Answer

Remi Vledder
Remi Vledder
14,144 Points
Remi Vledder
Remi Vledder
14,144 Points

They are roughly the same: https://stackoverflow.com/questions/45451141/what-is-the-difference-between-using-constructor-vs-state-to-declare-state

The first example you show is using a method called "class field declaration". The second is the "constructor method", as described in the official React docs.

Generally it's a matter of preference. The class field declaration I personally find a bit easier to read.