React JS: What means: "this.setState(defaultDogs);" in this code? : I'm evaluating a React application (see the code below). I know what is the meaning of setState props etc. and the overall working of it but I miss the meaning of the following: "this.setState(defaultDogs);"  

I wondered if that is a shorthand of the standard state update. I'm unsure if that update the Dogs state or add a new one instead. 

    React 16

    Here's the code where is that statement that is followed by // <<<<<<<<<<:

    import React, { Component } from 'react';
    import Dogs from './components/Dogs';
    import DogItem from './components/DogItem';
    import AddDog from './components/AddDog';
    import './App.css';
    
    class App extends Component {
      constructor() {
        super();
        this.state = {
          dogs: []
        };
      }
    
      getDogs() {
        var defaultDogs = {dogs: [
          {
            name: 'Princess',
            breed: 'Corgi',
            image: 'https://s-media-cache-ak0.pinimg.com/originals/51/ae/30/51ae30b78696b33a64661fa3ac205b3b.jpg'
          },
          {
            name: 'Riley',
            breed: 'Husky',
            image: 'http://portland.ohsohandy.com/images/uploads/93796/m/nice-and-sweet-siberian-husky-puppies-for-free-adoption.jpg'
          },
        ]};
        this.setState(defaultDogs); // <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
      }
    
      componentWillMount() {
        this.getDogs();
      }
    
      handleAddDog(dog) {
        let dogs = this.state.dogs;
        dogs.push(dog);
        this.setState({dogs:dogs});
      }
    
      handleDeleteDog(name) {
        let dogs = this.state.dogs;
        let index = dogs.findIndex(x => x.name === name);
        dogs.splice(index, 1);
        this.setState({dogs:dogs});
      }
    
      render() {
        return (
          <div className="App">
            <Dogs dogs={this.state.dogs} onDelete={this.handleDeleteDog.bind(this)} />
            <AddDog addDog={this.handleAddDog.bind(this)} />
            <hr />
          </div>
        
        );
      }
    }
    
    export default App;