xstate
Version:
Finite State Machines and Statecharts for the Modern Web.
501 lines (475 loc) • 14.5 kB
JavaScript
;
var guards_dist_xstateGuards = require('./raise-40b1a1f5.cjs.js');
// it's likely-ish that `(TActor & { src: TSrc })['logic']` would be faster
// but it's only possible to do it since https://github.com/microsoft/TypeScript/pull/53098 (TS 5.1)
// and we strive to support TS 5.0 whenever possible
function createSpawner(actorScope, {
machine,
context
}, event, spawnedChildren) {
const spawn = (src, options = {}) => {
const {
systemId,
input
} = options;
if (typeof src === 'string') {
const logic = guards_dist_xstateGuards.resolveReferencedActor(machine, src);
if (!logic) {
throw new Error(`Actor logic '${src}' not implemented in machine '${machine.id}'`);
}
const actorRef = guards_dist_xstateGuards.createActor(logic, {
id: options.id,
parent: actorScope.self,
syncSnapshot: options.syncSnapshot,
input: typeof input === 'function' ? input({
context,
event,
self: actorScope.self
}) : input,
src,
systemId
});
spawnedChildren[actorRef.id] = actorRef;
return actorRef;
} else {
const actorRef = guards_dist_xstateGuards.createActor(src, {
id: options.id,
parent: actorScope.self,
syncSnapshot: options.syncSnapshot,
input: options.input,
src,
systemId
});
return actorRef;
}
};
return (src, options) => {
const actorRef = spawn(src, options); // TODO: fix types
spawnedChildren[actorRef.id] = actorRef;
actorScope.defer(() => {
if (actorRef._processingStatus === guards_dist_xstateGuards.ProcessingStatus.Stopped) {
return;
}
actorRef.start();
});
return actorRef;
};
}
function resolveAssign(actorScope, snapshot, actionArgs, actionParams, {
assignment
}) {
if (!snapshot.context) {
throw new Error('Cannot assign to undefined `context`. Ensure that `context` is defined in the machine config.');
}
const spawnedChildren = {};
const assignArgs = {
context: snapshot.context,
event: actionArgs.event,
spawn: createSpawner(actorScope, snapshot, actionArgs.event, spawnedChildren),
self: actorScope.self,
system: actorScope.system
};
let partialUpdate = {};
if (typeof assignment === 'function') {
partialUpdate = assignment(assignArgs, actionParams);
} else {
for (const key of Object.keys(assignment)) {
const propAssignment = assignment[key];
partialUpdate[key] = typeof propAssignment === 'function' ? propAssignment(assignArgs, actionParams) : propAssignment;
}
}
const updatedContext = Object.assign({}, snapshot.context, partialUpdate);
return [guards_dist_xstateGuards.cloneMachineSnapshot(snapshot, {
context: updatedContext,
children: Object.keys(spawnedChildren).length ? {
...snapshot.children,
...spawnedChildren
} : snapshot.children
})];
}
/**
* Updates the current context of the machine.
*
* @param assignment An object that represents the partial context to update, or a
* function that returns an object that represents the partial context to update.
*
* @example
```ts
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()
}
})
}
}
});
```
*/
function assign(assignment) {
function assign(args, params) {
}
assign.type = 'xstate.assign';
assign.assignment = assignment;
assign.resolve = resolveAssign;
return assign;
}
function resolveEmit(_, snapshot, args, actionParams, {
event: eventOrExpr
}) {
const resolvedEvent = typeof eventOrExpr === 'function' ? eventOrExpr(args, actionParams) : eventOrExpr;
return [snapshot, {
event: resolvedEvent
}];
}
function executeEmit(actorScope, {
event
}) {
actorScope.defer(() => actorScope.emit(event));
}
/**
* Emits an event to event handlers registered on the actor via `actor.on(event, handler)`.
*
* @example
```ts
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'
// }
```
*/
function emit(
/**
* The event to emit, or an expression that returns an event to emit.
*/
eventOrExpr) {
function emit(args, params) {
}
emit.type = 'xstate.emit';
emit.event = eventOrExpr;
emit.resolve = resolveEmit;
emit.execute = executeEmit;
return emit;
}
/**
*
* @remarks
*
* `T | unknown` reduces to `unknown` and that can be problematic when it comes to contextual typing.
* It especially is a problem when the union has a function member, like here:
*
* ```ts
* declare function test(cbOrVal: ((arg: number) => unknown) | unknown): void;
* test((arg) => {}) // oops, implicit any
* ```
*
* This type can be used to avoid this problem. This union represents the same value space as `unknown`.
*/
// https://github.com/microsoft/TypeScript/issues/23182#issuecomment-379091887
// @TODO: Replace with native `NoInfer` when TS issue gets fixed:
// https://github.com/microsoft/TypeScript/pull/57673
/**
* @deprecated Use the built-in `NoInfer` type instead
*/
/**
* The full definition of an event, with a string `type`.
*/
/**
* The string or object representing the state value relative to the parent state node.
*
* @remarks
*
* - For a child atomic state node, this is a string, e.g., `"pending"`.
*
* - For complex state nodes, this is an object, e.g., `{ success: "someChildState" }`.
*/
// TODO: remove once TS fixes this type-widening issue
/** @deprecated use `AnyMachineSnapshot` instead */
// TODO: possibly refactor this somehow, use even a simpler type, and maybe even make `machine.options` private or something
/**
* @hidden
*/
let SpecialTargets = /*#__PURE__*/function (SpecialTargets) {
SpecialTargets["Parent"] = "#_parent";
SpecialTargets["Internal"] = "#_internal";
return SpecialTargets;
}({});
/**
* @deprecated Use `AnyActor` instead.
*/
// Based on RxJS types
/**
* @deprecated Use `Actor<T>` instead.
*/
// only meant to be used internally for debugging purposes
/**
* Represents logic which can be used by an actor.
*
* @template TSnapshot - The type of the snapshot.
* @template TEvent - The type of the event object.
* @template TInput - The type of the input.
* @template TSystem - The type of the actor system.
*/
function resolveSendTo(actorScope, snapshot, args, actionParams, {
to,
event: eventOrExpr,
id,
delay
}, extra) {
const delaysMap = snapshot.machine.implementations.delays;
if (typeof eventOrExpr === 'string') {
throw new Error(`Only event objects may be used with sendTo; use sendTo({ type: "${eventOrExpr}" }) instead`);
}
const resolvedEvent = typeof eventOrExpr === 'function' ? eventOrExpr(args, actionParams) : eventOrExpr;
let resolvedDelay;
if (typeof delay === 'string') {
const configDelay = delaysMap && delaysMap[delay];
resolvedDelay = typeof configDelay === 'function' ? configDelay(args, actionParams) : configDelay;
} else {
resolvedDelay = typeof delay === 'function' ? delay(args, actionParams) : delay;
}
const resolvedTarget = typeof to === 'function' ? to(args, actionParams) : to;
let targetActorRef;
if (typeof resolvedTarget === 'string') {
if (resolvedTarget === SpecialTargets.Parent) {
targetActorRef = actorScope.self._parent;
} else if (resolvedTarget === SpecialTargets.Internal) {
targetActorRef = actorScope.self;
} else if (resolvedTarget.startsWith('#_')) {
// SCXML compatibility: https://www.w3.org/TR/scxml/#SCXMLEventProcessor
// #_invokeid. If the target is the special term '#_invokeid', where invokeid is the invokeid of an SCXML session that the sending session has created by <invoke>, the Processor must add the event to the external queue of that session.
targetActorRef = snapshot.children[resolvedTarget.slice(2)];
} else {
targetActorRef = extra.deferredActorIds?.includes(resolvedTarget) ? resolvedTarget : snapshot.children[resolvedTarget];
}
if (!targetActorRef) {
throw new Error(`Unable to send event to actor '${resolvedTarget}' from machine '${snapshot.machine.id}'.`);
}
} else {
targetActorRef = resolvedTarget || actorScope.self;
}
return [snapshot, {
to: targetActorRef,
event: resolvedEvent,
id,
delay: resolvedDelay
}];
}
function retryResolveSendTo(_, snapshot, params) {
if (typeof params.to === 'string') {
params.to = snapshot.children[params.to];
}
}
function executeSendTo(actorScope, params) {
// this forms an outgoing events queue
// thanks to that the recipient actors are able to read the *updated* snapshot value of the sender
actorScope.defer(() => {
const {
to,
event,
delay,
id
} = params;
if (typeof delay === 'number') {
actorScope.system.scheduler.schedule(actorScope.self, to, event, delay, id);
return;
}
actorScope.system._relay(actorScope.self,
// at this point, in a deferred task, it should already be mutated by retryResolveSendTo
// if it initially started as a string
to, event.type === guards_dist_xstateGuards.XSTATE_ERROR ? guards_dist_xstateGuards.createErrorActorEvent(actorScope.self.id, event.data) : event);
});
}
/**
* Sends an event to an actor.
*
* @param actor The `ActorRef` to send the event to.
* @param event The event to send, or an expression that evaluates to the event to send
* @param options Send action options
* - `id` - The unique send event identifier (used with `cancel()`).
* - `delay` - The number of milliseconds to delay the sending of the event.
*/
function sendTo(to, eventOrExpr, options) {
function sendTo(args, params) {
}
sendTo.type = 'xsnapshot.sendTo';
sendTo.to = to;
sendTo.event = eventOrExpr;
sendTo.id = options?.id;
sendTo.delay = options?.delay;
sendTo.resolve = resolveSendTo;
sendTo.retryResolve = retryResolveSendTo;
sendTo.execute = executeSendTo;
return sendTo;
}
/**
* Sends an event to this machine's parent.
*
* @param event The event to send to the parent machine.
* @param options Options to pass into the send event.
*/
function sendParent(event, options) {
return sendTo(SpecialTargets.Parent, event, options);
}
/**
* Forwards (sends) an event to the `target` actor.
*
* @param target The target actor to forward the event to.
* @param options Options to pass into the send action creator.
*/
function forwardTo(target, options) {
return sendTo(target, ({
event
}) => event, options);
}
function resolveEnqueueActions(actorScope, snapshot, args, actionParams, {
collect
}) {
const actions = [];
const enqueue = function enqueue(action) {
actions.push(action);
};
enqueue.assign = (...args) => {
actions.push(assign(...args));
};
enqueue.cancel = (...args) => {
actions.push(guards_dist_xstateGuards.cancel(...args));
};
enqueue.raise = (...args) => {
// for some reason it fails to infer `TDelay` from `...args` here and picks its default (`never`)
// then it fails to typecheck that because `...args` use `string` in place of `TDelay`
actions.push(guards_dist_xstateGuards.raise(...args));
};
enqueue.sendTo = (...args) => {
// for some reason it fails to infer `TDelay` from `...args` here and picks its default (`never`)
// then it fails to typecheck that because `...args` use `string` in place of `TDelay
actions.push(sendTo(...args));
};
enqueue.spawnChild = (...args) => {
actions.push(guards_dist_xstateGuards.spawnChild(...args));
};
enqueue.stopChild = (...args) => {
actions.push(guards_dist_xstateGuards.stopChild(...args));
};
enqueue.emit = (...args) => {
actions.push(emit(...args));
};
collect({
context: args.context,
event: args.event,
enqueue,
check: guard => guards_dist_xstateGuards.evaluateGuard(guard, snapshot.context, args.event, snapshot),
self: actorScope.self,
system: actorScope.system
}, actionParams);
return [snapshot, undefined, actions];
}
/**
* Creates an action object that will execute actions that are queued by the `enqueue(action)` function.
*
* @example
```ts
import { createMachine, enqueueActions } from 'xstate';
const machine = createMachine({
entry: enqueueActions(({ enqueue, check }) => {
enqueue.assign({ count: 0 });
if (check('someGuard')) {
enqueue.assign({ count: 1 });
}
enqueue('someAction');
})
})
```
*/
function enqueueActions(collect) {
function enqueueActions(args, params) {
}
enqueueActions.type = 'xstate.enqueueActions';
enqueueActions.collect = collect;
enqueueActions.resolve = resolveEnqueueActions;
return enqueueActions;
}
function resolveLog(_, snapshot, actionArgs, actionParams, {
value,
label
}) {
return [snapshot, {
value: typeof value === 'function' ? value(actionArgs, actionParams) : value,
label
}];
}
function executeLog({
logger
}, {
value,
label
}) {
if (label) {
logger(label, value);
} else {
logger(value);
}
}
/**
*
* @param expr The expression function to evaluate which will be logged.
* Takes in 2 arguments:
* - `ctx` - the current state context
* - `event` - the event that caused this action to be executed.
* @param label The label to give to the logged expression.
*/
function log(value = ({
context,
event
}) => ({
context,
event
}), label) {
function log(args, params) {
}
log.type = 'xstate.log';
log.value = value;
log.label = label;
log.resolve = resolveLog;
log.execute = executeLog;
return log;
}
exports.SpecialTargets = SpecialTargets;
exports.assign = assign;
exports.emit = emit;
exports.enqueueActions = enqueueActions;
exports.forwardTo = forwardTo;
exports.log = log;
exports.sendParent = sendParent;
exports.sendTo = sendTo;