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: "parameterProvider",
    context: {
      retryCount: 0,
      value: null,
      error: null
    },
    type: "parallel",
    states: {
      update: {
        initial: "initializing",
        states: {
          initializing: {
            entry: assign(context => ({
              ...context,
              retryCount: 0
            })),
            always: "transit"
          },
          error: {
            type: "final",
            entry: [send("ERROR"), "signal error"]
          },
          success: {
            type: "final",
            entry: send("VALIDATED")
          },
          transit: {
            after: {
              [10000]: {
                target: "error",
                actions: [
                  assign(context => ({ ...context, error: "Hard timeout" }))
                ]
              }
            },
            invoke: {
              src: "fetch parameters",
              onDone: {
                target: "validating",
                actions: [
                  assign((context, event) => ({
                    ...context,
                    value: event.data
                  }))
                ]
              },
              onError: [
                {
                  target: "coolDown",
                  cond: context => context.retryCount < 10,
                  actions: [
                    assign(context => ({
                      ...context,
                      retryCount: context.retryCount + 1
                    }))
                  ]
                },
                {
                  target: "error",
                  actions: [
                    assign((context, event) => ({
                      ...context,
                      error: event.data
                    }))
                  ]
                }
              ]
            }
          },
          coolDown: {
            after: { [1000]: "transit" }
          },
          validating: {
            invoke: {
              src: "validate parameters",
              onDone: "success",
              onError: {
                target: "error",
                actions: [
                  assign((context, event) => ({
                    ...context,
                    error: event.data
                  }))
                ]
              }
            }
          }
        },
        on: {
          INVALIDATE: "update",
          UPDATE: "update"
        }
      },
      value: {
        initial: "uninitialized",
        states: {
          uninitialized: {
            on: {
              VALIDATED: "valid", // could have guarded action that sends "actually changed" event
              ERROR: "invalid"
            }
          },
          valid: {
            entry: "declare valid",
            on: {
              ERROR: "invalid",
              INVALIDATE: "invalid"
            }
          },
          invalid: {
            entry: "declare invalid",
            on: {
              VALIDATED: "valid" // could have guarded action that sends "actually changed" event
            }
          }
        }
      }
    }
  });