super()
will call the constructor
of its parent
class. This is required when you need to access some variables from the parent class.
In React, when you call super
with props, React will make props
available across the component through this.props
. See example 2 below
without super()
class A {
constructor() {
this.a="hello"
}
}
class B extends A {
constructor(){
console.log(this.a) //throws an error
}
}
console.log(new B())
with super()
class A {
constructor(props) {
this.props = props
}
}
class B extends A {
constructor(props) {
super(props)
console.log(this.props)
}
}
console.log(new B({title: 'hello world'}))
Hope this helps!