Generated by XState Viz: https://xstate.js.org/viz

machine.js

Machine({
  id: 'a',
    initial: 'checking_url',
    context: {gistID: null, gistRawContent: null},
    states: {
        checking_url: {
            entry: 'parseQueries',
            always: [
                { target: 'with_gist', cond: 'isGistIDAvailable' },
                { target: 'no_gist' }
            ]
        },
        with_gist: {
            initial: 'loading_content',
            states: {
                loading_content: {
                    invoke: {
                        src: 'loadGistContent',
                        onDone: {
                            target: 'gist_loaded',
                            actions: [(_, e) => e.data]
                        },
                        onError: {
                            target: 'gist_error',
                            actions: ['showError']
                        }
                    }
                },
                gist_loaded: {
                    type: 'final'
                },
                gist_error: {
                    type: 'final'
                }
            }
        },
        no_gist: {
            type: 'final'
        }
    }
}, {
    actions: {
        parseQueries: assign({
            gistID: new URLSearchParams(window.location.search).get('gist')
        })
    },
    guards: {
        isGistIDAvailable: ctx => !!ctx.gistID
    },
    services: {
        loadGistContent: ctx => {
            return fetch('https://api.github.com/gist/' + ctx.gistID).then(resp => {
                if (resp.status === 404) {
                    return Promise.reject(Error('Gist not found'))
                }
            })
        }
    }
})