Reset initial state in React + ES6

Question

I have a class, ElementBuilder below, and when the user saves the Element they've built, I want the state to reset to the values below.

I have some functions in this class that I haven't provided but that change the state of title , size , and color .

In ES 5, I would have a getInitialState function on my class and could call this.getInitialState() in a function.

This element lives in my app for the lifecycle of a logged in user and I want the default values to always be the same regardless of past usage.

How do I achieve this without writing a function that sets an object of default values (or maybe that's the answer)? thanks!

class ElementBuilder extends Component {
    constructor(props) {
        super(props);

        this.state = {
            title: 'Testing,
            size: 100,
            color: '#4d96ce',
        };
    }

    resetBuilder() {
        this.setState({ this.getInitialState() });
    }
}

Answer 1

You may use a getter function:

class ElementBuilder extends Component {
  constructor(props) {
    super(props);

    this.state = this.initialState;
  }

  get initialState() {
    return {
      title: 'Testing',
      size: 100,
      color: '#4d96ce',
    };
  }

  resetBuilder() {
    this.setState(this.initialState);
  }
}

or just a variable:

constructor(props) {
  super(props);

  this.initialState = {
    title: 'Testing',
    size: 100,
    color: '#4d96ce',
  };
  this.state = this.initialState;
}

Answer 2

Using the proposed class fields, you could do something like this:

class ElementBuilder extends Component {
    static initialState = {
        title: 'Testing',
        size: 100,
        color: '#4d96ce'
    }
    
    constructor(props) {
        super(props)

        this.state = ElementBuilder.initialState
    }

    resetBuilder() {
        this.setState(ElementBuilder.initialState)
    }
}

Answer 3

Since the initial state doesn't seem to depend on anything instance specific, just define the value outside the class:

const initialState = {...};

class ElementBuilder extends Component {
    constructor(props) {
        super(props);

        this.state = initialState;
    }

    resetBuilder() {
        this.setState(initialState);
    }
}

Answer 4

Use an High Order Component to clear component state (rerender)

Exemple Element.jsx :

// Target ----- //

class Element extends Component {

  constructor(props){
    super(props)
    const {
        initState = {}
    } = props
    this.state = {initState}
  }

  render() {
    return (
        <div className="element-x">
            {...}
        </div>
    )
  }
}

// Target Manager ----- //

class ElementMgr extends Component {

    constructor(props){
        super(props)
        const {
            hash = 0
        } = props
        this.state = {
            hash, // hash is a post.id 
            load: false
        }
    }

    render() {
        const {load} = this.state
        if (load) {
            return (<div className="element-x"/>)
        } else {
            return (<Element {...this.props}/>)
        }
    }

    componentWillReceiveProps(nextProps) {
        const {hash = 0} = nextProps
        if (hash !== this.state.hash) {
            this.setState({load:true})
            setTimeout(() => this.setState({
                hash,
                load:false
            }),0)
        }
    }
}

export default ElementMgr