What is the meaning for let {} =?

Question

What is the difference between these two lines of code?

let { fadeAnim } = this.state;

vs

let fadeAnim = this.state;?

Answer 1

If this.state is a reference to an object, then

let { fadeAnim } = this.state;

is like

let fadeAnim = this.state.fadeAnim;

It's a destructuring assignment that implicitly extracts one or more properties from an object (just one in this case).

Answer 2

let { fadeAnim } = this.state;

Equals

let fadeAnim = this.state.fadeAnim;

It’s called destructuring assignment: https://developer.mozilla.org/nl/docs/Web/JavaScript/Reference/Operatoren/Destructuring_assignment