有没有办法在useEffect的反应组件中设置xstate机的state？

Question

I have the following React.js component that needs the following:

• Persist the state when a button is clicked through using fetch to call a server side API.
• When the component is initialized that the state is set in the component after calling useEffect that uses fetch to call a server side API to get the current state of the object.

Here is the display of the component

---

---

Here is what I have so far.

import React, { useEffect, useState } from 'react';
import { useParams, useHistory } from "react-router-dom";
import { createMachine } from 'xstate';
import { useMachine } from "@xstate/react";
import {MagellanButton} from "./Styles";
import 'bootstrap/dist/css/bootstrap.min.css';
import '../App.css';

const approvalMachine = createMachine({
    id: 'approve',
    initial: 'Not Submitted',
    context: {
        retries: 0
    },
    states: {
        'Not Submitted': {
            on: {
                SUBMIT: 'Pending Approval'
            }
        },
        'Pending Approval': {
            on: {
                CANCEL: 'Not Submitted',
                CHANGE: 'Change Request',
                DENIED: 'Denied',
                APPROVED: 'Approved'
            }
        },
        'Change Request': {
            on: {
                RESUBMITTED: 'Pending Approval',
                CANCEL: 'Not Submitted'
            }
        },
        Denied: {
            type: 'final'
        },
        Approved: {
            on: {
                PUBLISH: 'Published'
            }
        },
        Published: {
            type: "final"
        }
    }
});

function MagellanStateManager({id}) {
    const parameters = useParams();
    const history = useHistory()
    const [state, send] = useMachine(approvalMachine);

    useEffect(() => {
    }, []);

    return (
        <span style={{float: "right", marginTop: 8}}>
            <span className="m-form-label  ml-3">State:</span> <span>{state.value}</span>
            <MagellanButton className="ml-3" disabled={!state.nextEvents.includes('SUBMIT')} onClick={() => send('SUBMIT')}>Submit</MagellanButton>
            <MagellanButton className="ml-3" disabled={!state.nextEvents.includes('CANCEL')} onClick={() => send('CANCEL')}>Cancel</MagellanButton>
            <MagellanButton className="ml-3" disabled={!state.nextEvents.includes('CHANGE')} onClick={() => send('CHANGE')}>Change</MagellanButton>
            <MagellanButton className="ml-3" disabled={!state.nextEvents.includes('RESUBMITTED')} onClick={() => send('RESUBMITTED')}>Resubmit</MagellanButton>
            <MagellanButton className="ml-3" disabled={!state.nextEvents.includes('DENIED')} onClick={() => send('DENIED')}>Deny</MagellanButton>
            <MagellanButton className="ml-3" disabled={!state.nextEvents.includes('APPROVED')} onClick={() => send('APPROVED')}>Approve</MagellanButton>
            <MagellanButton className="ml-3" disabled={!state.nextEvents.includes('PUBLISH')} onClick={() => send('PUBLISH')}>Publish</MagellanButton>
        </span>
    )

}

export default MagellanStateManager;

Answer 1

From the comment from Taxel, I was able to find my solution. Here is the changed react element. I would appreciate any additional comments to make this even better.

Thank You!

import React, {useEffect, useState} from 'react';
import { createMachine, interpret } from 'xstate';
import {MagellanButton} from "./Styles";
import 'bootstrap/dist/css/bootstrap.min.css';
import '../App.css';

const approvalMachine = createMachine({
    id: 'approve',
    initial: 'Not Submitted',
    context: {
        retries: 0
    },
    states: {
        'Not Submitted': {
            on: {
                SUBMIT: 'Pending Approval'
            }
        },
        'Pending Approval': {
            on: {
                CANCEL: 'Not Submitted',
                CHANGE: 'Change Request',
                DENIED: 'Denied',
                APPROVED: 'Approved'
            }
        },
        'Change Request': {
            on: {
                RESUBMITTED: 'Pending Approval',
                CANCEL: 'Not Submitted'
            }
        },
        Denied: {
            type: 'final'
        },
        Approved: {
            on: {
                PUBLISH: 'Published'
            }
        },
        Published: {
            type: "final"
        }
    }
});

function MagellanStateManager({id}) {
    const [service, setService] = useState(interpret(approvalMachine));
    const [counter, setCounter] = useState(0);

    useEffect(() => {
        // TODO: Add the fetch to get the stored state from the server
        const approvalService = interpret(approvalMachine);
        approvalService.start(approvalMachine.initialState);
        setService(approvalService);
        // TODO: Add dependencies for the useEffect for when identification values change
    }, []);

    function storeState(theEvent) {
        const newState = service.send(theEvent);
        const theState = JSON.stringify(newState);
        // TODO: Add the fetch to send the state to the server to be stored
        console.log(theState);
        setCounter(counter + 1);
    }

    function notEvent(theEvent) {
        if (service != null && service._state != null) {
            return !service._state.nextEvents.includes(theEvent);
        } else {
            return true;
        }
    }

    return (
        <span style={{float: "right", marginTop: 8}}>
            <span className="m-form-label  ml-3">State:</span> <span>{service ? service._state ? service._state.value : "" : ""}</span>
            <MagellanButton className="ml-3" disabled={notEvent('SUBMIT')} onClick={() => storeState('SUBMIT')}>Submit</MagellanButton>
            <MagellanButton className="ml-3" disabled={notEvent('CANCEL')} onClick={() => storeState('CANCEL')}>Cancel</MagellanButton>
            <MagellanButton className="ml-3" disabled={notEvent('CHANGE')} onClick={() => storeState('CHANGE')}>Change</MagellanButton>
            <MagellanButton className="ml-3" disabled={notEvent('RESUBMITTED')} onClick={() => storeState('RESUBMITTED')}>Resubmit</MagellanButton>
            <MagellanButton className="ml-3" disabled={notEvent('DENIED')} onClick={() => storeState('DENIED')}>Deny</MagellanButton>
            <MagellanButton className="ml-3" disabled={notEvent('APPROVED')} onClick={() => storeState('APPROVED')}>Approve</MagellanButton>
            <MagellanButton className="ml-3" disabled={notEvent('PUBLISH')} onClick={() => storeState('PUBLISH')}>Publish</MagellanButton>
        </span>
    )

}

export default MagellanStateManager;