Variable xstateConst

Type declaration

• assign: (<TContext, TExpressionEvent, TParams, TEvent, TActor>(assignment: Assigner<LowInfer<TContext>, TExpressionEvent, TParams, TEvent, TActor> | PropertyAssigner<LowInfer<TContext>, TExpressionEvent, TParams, TEvent, TActor>) => ActionFunction<TContext, TExpressionEvent, TEvent, TParams, TActor, never, never, never, never>)

  • • <TContext, TExpressionEvent, TParams, TEvent, TActor>(assignment): ActionFunction<TContext, TExpressionEvent, TEvent, TParams, TActor, never, never, never, never>

    • Updates the current context of the machine.

      Type Parameters

      • TContext extends MachineContext
      • TExpressionEvent extends AnyEventObject
      • TParams extends NonReducibleUnknown
      • TEvent extends EventObject
      • TActor extends ProvidedActor

      Parameters

      • assignment: Assigner<LowInfer<TContext>, TExpressionEvent, TParams, TEvent, TActor> | PropertyAssigner<LowInfer<TContext>, TExpressionEvent, TParams, TEvent, TActor>

        An object that represents the partial context to update, or a function that returns an object that represents the partial context to update.

      Returns ActionFunction<TContext, TExpressionEvent, TEvent, TParams, TActor, never, never, never, never>

      Example

      import { createMachine, assign } from 'xstate';
      
      const countMachine = createMachine({
        context: {
          count: 0,
          message: ''
        },
        on: {
          inc: {
            actions: assign({
              count: ({ context }) => context.count + 1
            })
          },
          updateMessage: {
            actions: assign(({ context, event }) => {
              return {
                message: event.message.trim()
              };
            })
          }
        }
      });
      Copy

• emit: (<TContext, TExpressionEvent, TParams, TEvent, TEmitted>(eventOrExpr: DoNotInfer<TEmitted> | SendExpr<TContext, TExpressionEvent, TParams, DoNotInfer<TEmitted>, TEvent>) => ActionFunction<TContext, TExpressionEvent, TEvent, TParams, never, never, never, never, TEmitted>)

  • • <TContext, TExpressionEvent, TParams, TEvent, TEmitted>(eventOrExpr): ActionFunction<TContext, TExpressionEvent, TEvent, TParams, never, never, never, never, TEmitted>

    • Emits an event to event handlers registered on the actor via actor.on(event, handler).

      Type Parameters

      • TContext extends MachineContext
      • TExpressionEvent extends EventObject
      • TParams extends NonReducibleUnknown
      • TEvent extends EventObject
      • TEmitted extends AnyEventObject

      Parameters

      • eventOrExpr: DoNotInfer<TEmitted> | SendExpr<TContext, TExpressionEvent, TParams, DoNotInfer<TEmitted>, TEvent>

        The event to emit, or an expression that returns an event to emit.

      Returns ActionFunction<TContext, TExpressionEvent, TEvent, TParams, never, never, never, never, TEmitted>

      Example

      import { emit } from 'xstate';
      
      const machine = createMachine({
        // ...
        on: {
          something: {
            actions: emit({
              type: 'emitted',
              some: 'data'
            })
          }
        }
        // ...
      });
      
      const actor = createActor(machine).start();
      
      actor.on('emitted', (event) => {
        console.log(event);
      });
      
      actor.send({ type: 'something' });
      // logs:
      // {
      //   type: 'emitted',
      //   some: 'data'
      // }
      Copy