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

machine.js

const assignByValue = name => assign({ [name]: (context, event) => event.value });
const addProduct = (logic, product) =>
  assign({
    products: (c, e) => (logic(c, e) ? c.products.concat(product) : c.products),
  });

const installCostsMachine = Machine(
  {
    id: 'install_costs',
    initial: 'idle',
    context: {
      additionalFaces: 0,
      additionalStories: 0,
      complexInstall: false,
      inRoof: false,
      isBatteryPackage: false,
      isEvReady: false,
      isPvPackage: false,
      panelCount: 0,
      rosemarySlate: false,
      trenching: 0,
      products: [],
    },
    states: {
      idle: {
        on: {
          ADDITIONAL_FACES: { target: 'calculating', actions: 'additionalFaces' },
          ADDITIONAL_STORIES: { target: 'calculating', actions: 'additionalStories' },
          COMPLEX_INSTALL: { target: 'calculating', actions: 'complexInstall' },
          IN_ROOF: { target: 'calculating', actions: 'inRoof' },
          IS_BATTERY_PACKAGE: { target: 'calculating', actions: 'isBatteryPackage' },
          IS_EV_READY: { target: 'calculating', actions: 'isEvReady' },
          IS_PV_PACKAGE: { target: 'calculating', actions: 'isPvPackage' },
          PANEL_COUNT: { target: 'calculating', actions: 'panelCount' },
          ROSEMARY_SLATE: { target: 'calculating', actions: 'rosemarySlate' },
          TRENCHING: { target: 'calculating', actions: 'trenching' },
        },
      },
      calculating: {
        on: {
          '': {
            // Transient transition
            target: 'idle',
            actions: ['clearProducts', 'checkBaseInstall', 'checkScaffoldFacesXStoreys', 'logContext'],
          },
        },
      },
    },
  },
  {
    actions: {
      additionalFaces: assignByValue('additionalFaces'),
      additionalStories: assignByValue('additionalStories'),
      checkBaseInstall: addProduct(c => c.isPvPackage, { prod_id: 'BASE-INSTALL' }),
      checkScaffoldFacesXStoreys: addProduct(c => c.additionalFaces > 1 && c.additionalStories > 1, {
        prod_id: 'SCAFF-FACES-X-STOREYS',
      }),
      clearProducts: assign({ products: (c, e) => [] }),
      complexInstall: assignByValue('complexInstall'),
      inRoof: assignByValue('inRoof'),
      isBatteryPackage: assignByValue('isBatteryPackage'),
      isEvReady: assignByValue('isEvReady'),
      isPvPackage: assignByValue('isPvPackage'),
      logContext: (c, e) => console.log(c),
      panelCount: assignByValue('panelCount'),
      rosemarySlate: assignByValue('rosemarySlate'),
      trenching: assignByValue('trenching'),
    },
  }
);