import { is, type Unit } from "effector";

Namespace for unit validators.

Methods

is.store(value)

Checks if given value is store

Returns

boolean β€” Type-guard

Examples

import { is, createStore, createEvent, createEffect, createDomain } from "effector";


const $store = createStore(null);
const event = createEvent();
const fx = createEffect();


is.store($store);
// => true


is.store(event);
// => false


is.store(fx);
// => false


is.store(createDomain());
// => false


is.store(fx.pending);
// => true


is.store(fx.done);
// => false


is.store($store.updates);
// => false


is.store(null);
// => false

Try it

is.event(value)

Checks if given value is event

Returns

boolean β€” Type-guard

Examples

import { is, createStore, createEvent, createEffect, createDomain } from "effector";


const $store = createStore(null);
const event = createEvent();
const fx = createEffect();


is.event($store);
// => false


is.event(event);
// => true


is.event(fx);
// => false


is.event(createDomain());
// => false


is.event(fx.pending);
// => false


is.event(fx.done);
// => true


is.event($store.updates);
// => true


is.event(null);
// => false

Try it

is.effect(value)

Checks if given value is effect

Returns

boolean β€” Type-guard

Examples

import { is, createStore, createEvent, createEffect, createDomain } from "effector";


const $store = createStore(null);
const event = createEvent();
const fx = createEffect();


is.effect($store);
// => false


is.effect(event);
// => false


is.effect(fx);
// => true


is.effect(createDomain());
// => false


is.effect(null);
// => false

Try it

is.targetable

Checks if given value can be used in operators target (or be called as a function in case of events)

Returns

boolean β€” Type-guard

Examples

import { is, createStore, createEvent, createEffect } from "effector";


const $store = createStore(null);
const $mapped = $store.map((x) => x);
const event = createEvent();
const mappedEvent = event.map((x) => x);
const fx = createEffect();


is.targetable($store);
// => true


is.targetable($mapped);
// => false


is.targetable(event);
// => true


is.targetable(mappedEvent);
// => false


is.targetable(fx);
// => true

is.domain(value)

Checks if given value is domain

Returns

boolean β€” Type-guard

Examples

import { is, createStore, createEvent, createEffect, createDomain } from "effector";


const $store = createStore(null);
const event = createEvent();
const fx = createEffect();


is.domain($store);
// => false


is.domain(event);
// => false


is.domain(fx);
// => false


is.domain(createDomain());
// => true


is.domain(null);
// => false

Try it

is.scope(value)

since

effector 22.0.0

Checks if given value is scope since effector 22.0.0.

Returns

boolean β€” Type-guard

Examples

import { fork } from "effector";


const $store = createStore(null);
const event = createEvent();
const fx = createEffect();
const scope = fork();


is.scope(scope);
// => true


is.scope($store);
// => false


is.scope(event);
// => false


is.scope(fx);
// => false


is.scope(createDomain());
// => false


is.scope(null);
// => false

Try it

is.unit(value)

Checks if given value is Unit: Store, Event, Effect, Domain or Scope

Returns

boolean β€” Type-guard

Examples

import { is, createStore, createEvent, createEffect, createDomain, fork } from "effector";


const $store = createStore(null);
const event = createEvent();
const fx = createEffect();
const scope = fork();


is.unit(scope);
// => true


is.unit($store);
// => true


is.unit(event);
// => true


is.unit(fx);
// => true


is.unit(createDomain());
// => true


is.unit(fx.pending);
// => true


is.unit(fx.done);
// => true


is.unit($store.updates);
// => true


is.unit(null);
// => false

Try it

is.attached(value)

since

effector 22.4.0

Checks if given value is effect created via attach method. If passed not an effect, returns false.

Returns

boolean β€” Type-guard

Usage

Sometimes you need to add an error log on effects failures, but only on effects that have been β€œlocalized” via attach. If you leave onCreateEffect as it is, without checks, the error log will be duplicated, because it will happen on the parent and the child effect.

import { createDomain, attach, is } from "effector";


const logFailuresDomain = createDomain();


logFailuresDomain.onCreateEffect((effect) => {
  if (is.attached(effect)) {
    effect.fail.watch(({ params, error }) => {
      console.warn(`Effect "${effect.compositeName.fullName}" failed`, params, error);
    });
  }
});


const baseRequestFx = logFailuresDomain.createEffect((path) => {
  throw new Error(`path ${path}`);
});


const loadDataFx = attach({
  mapParams: () => "/data",
  effect: baseRequestFx,
});


const loadListFx = attach({
  mapParams: () => "/list",
  effect: baseRequestFx,
});


loadDataFx();
loadListFx();

Try it

Examples

import { is, createStore, createEvent, createEffect, createDomain, attach } from "effector";


const $store = createStore(null);
const event = createEvent();
const fx = createEffect();


const childFx = attach({
  effect: fx,
});


is.attached(childFx);
// => true


is.attached(fx);
// => false


is.attached($store);
// => false


is.attached(event);
// => false


is.attached(createDomain());
// => false


is.attached(null);
// => false

Try it

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