Function createEvent

src/effector/createUnit.ts:152–226

(
  nameOrConfig?: any,
  maybeConfig?: any,
)

}

export function createEvent<Payload = any>(
  nameOrConfig?: any,
  maybeConfig?: any,
): Event<Payload> {
  const config = flattenConfig({
    or: maybeConfig,
    and: typeof nameOrConfig === 'string' ? {name: nameOrConfig} : nameOrConfig,
  }) as any
  const errorTitle = generateErrorTitle('event', config)
  const event = ((payload: Payload, ...args: unknown[]) => {
    assert(
      !getMeta(event, 'derived'),
      'call of derived event is not supported, use createEvent instead',
      errorTitle,
    )
    assert(
      !isPure,
      'unit call from pure function is not supported, use operators like sample instead',
      errorTitle,
    )
    if (currentPage) {
      return callCreate(event, template, payload, args)
    }
    return event.create(payload, args)
  }) as Event<Payload>
  const template = readTemplate()
  const finalEvent = Object.assign(event, {
    graphite: createNode({
      meta: initUnit(
        config.actualOp || EVENT,
        event,
        config,
        getUnitTrace(createEvent),
      ),
      regional: true,
    }),
    create(params: Payload, _: any[]) {
      launch({target: event, params, scope: forkPage!})
      return params
    },
    watch: (fn: (payload: Payload) => any) => watchUnit(event, fn),
    map: (fn: Function) => deriveEvent(event, MAP, fn, [userFnCall()]),
    filter: (fn: {fn: Function}) =>
      //@ts-expect-error
      deriveEvent(event, 'filter', fn.fn ? fn : fn.fn, [
        userFnCall(callStack, true),
      ]),
    filterMap: (fn: Function) =>
      deriveEvent(event, 'filterMap', fn, [
        userFnCall(),
        calc(value => !isVoid(value), true),
      ]),
    prepend(fn: Function) {
      assert(
        // @ts-expect-error
        event.targetable,
        '.prepend of derived event is not supported, call source event instead',
        errorTitle,