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

machine.js

  // Available variables:
  // - Machine
  // - interpret
  // - assign
  // - send
  // - sendParent
  // - spawn
  // - raise
  // - actions
  // - XState (all XState exports)
  
  const fetchMachine = Machine(
  {
    id: 'fetch-machine',
    initial: 'idle',
    context: {
      q: '',
      offset: 0,
      results: [],
      filters: {},
      error: '',
      query: '', // the search term in the box
    },
    states: {
      idle: {
        on: {
          FETCH_RESULTS: {
            target: 'pending',
            actions: 'updateParams',
            cond: 'checkQuery',
          },
        },
      },
      pending: {
        // injected when the state machine is invoked
        // redirects the application to the correct URL
        entry: ['redirectToSearch'],
        on: {
          LOAD_RESULTS: {
            target: 'success',
            actions: 'loadData',
          },
          ERROR: {
            target: 'failure',
            actions: 'assignError',
          },
        },
      },
      success: {
        on: {
          FETCH_RESULTS: {
            target: 'pending',
            actions: 'updateParams',
            cond: 'checkQuery',
          },
          TOGGLE_FILTER: {
            target: 'pending',
            actions: 'toggleFilter',
          },
          CLEAR_FILTER: {
            target: 'pending',
            actions: 'clearFilter',
          },
        },
      },
      retry: {
        invoke: {
          id: 'retry-fetch',
          // injected when the state machine is invoked
          // retries the API request
          src: 'invokeRetryFetch',
          onDone: {
            target: 'success',
            actions: 'loadData',
          },
          onError: {
            target: 'failure',
            actions: 'assignError',
          },
        },
      },
      failure: {
        on: {
          FETCH_RESULTS: {
            target: 'retry',
            actions: 'updateParams',
          },
        },
      },
    },
    on: {
      LOAD_RESULTS: {
        target: 'success',
        actions: 'loadData',
      },
      ERROR: {
        target: 'failure',
        actions: 'assignError',
      },
      RESET: {
        target: 'idle',
        actions: 'resetData',
      },
      SET_QUERY: {
        target: 'idle',
        actions: 'setQuery',
      },
    },
  },
  {
    actions: {
      assignError: assign((ctx, evt) => ({
        ...ctx,
        error: evt.data?.message,
        query: evt.data?.query || ctx.query,
      })),
      setQuery: assign((_, evt) => ({
        query: evt.query || '',
      })),
      updateParams: assign((ctx) => ({
        q: ctx.query,
        offset: 0,
      })),
      loadData: assign((ctx, evt) => {
        return {
          q: evt.data.q || '',
          query: evt.data.q || '',
          offset: evt.data.offset || 0,
          results: evt.data.results || [],
          filters: addMissingFilters(
            ctx.filters,
            evt.data.filters,
            evt.data.selected
          ),
          error: null,
        };
      }),
      resetData: assign((_ctx) => ({
        q: '',
        results: [],
        filters: {},
        error: '',
      })),
      toggleFilter: assign((ctx, evt) => {
        const selected = ctx.filters[evt.key]?.selected || new Set();
        if (selected.has(evt.id)) {
          selected.delete(evt.id);
        } else {
          selected.add(evt.id);
        }

        return {
          offset: 0,
          filters: {
            ...ctx.filters,
            [evt.key]: {
              ...ctx.filters[evt.key],
              selected,
            },
          },
        };
      }),
      clearFilter: assign((ctx, evt) => ({
        filters: {
          ...ctx.filters,
          [evt.key]: {
            ...ctx.filters[evt.key],
            selected: new Set(),
          },
        },
      })),
    },
    guards: {
      checkQuery: (ctx) => ctx.q !== ctx.query,
      checkFilterSelection: (ctx, evt) =>
        ctx.filters[evt.key]?.selected?.size > 0,
    },
  }
)