next/dist/esm/shared/lib/router/action-queue.js

The React Framework

import { ACTION_REFRESH, ACTION_SERVER_ACTION, ACTION_NAVIGATE, ACTION_RESTORE } from '../../../client/components/router-reducer/router-reducer-types';
import { reducer } from '../../../client/components/router-reducer/router-reducer';
import { startTransition } from 'react';
import { isThenable } from '../is-thenable';
function runRemainingActions(actionQueue, setState) {
    if (actionQueue.pending !== null) {
        actionQueue.pending = actionQueue.pending.next;
        if (actionQueue.pending !== null) {
            // eslint-disable-next-line @typescript-eslint/no-use-before-define
            runAction({
                actionQueue,
                action: actionQueue.pending,
                setState
            });
        } else {
            // No more actions are pending, check if a refresh is needed
            if (actionQueue.needsRefresh) {
                actionQueue.needsRefresh = false;
                actionQueue.dispatch({
                    type: ACTION_REFRESH,
                    origin: window.location.origin
                }, setState);
            }
        }
    }
}
async function runAction(param) {
    let { actionQueue, action, setState } = param;
    const prevState = actionQueue.state;
    actionQueue.pending = action;
    const payload = action.payload;
    const actionResult = actionQueue.action(prevState, payload);
    function handleResult(nextState) {
        // if we discarded this action, the state should also be discarded
        if (action.discarded) {
            return;
        }
        actionQueue.state = nextState;
        runRemainingActions(actionQueue, setState);
        action.resolve(nextState);
    }
    // if the action is a promise, set up a callback to resolve it
    if (isThenable(actionResult)) {
        actionResult.then(handleResult, (err)=>{
            runRemainingActions(actionQueue, setState);
            action.reject(err);
        });
    } else {
        handleResult(actionResult);
    }
}
function dispatchAction(actionQueue, payload, setState) {
    let resolvers = {
        resolve: setState,
        reject: ()=>{}
    };
    // most of the action types are async with the exception of restore
    // it's important that restore is handled quickly since it's fired on the popstate event
    // and we don't want to add any delay on a back/forward nav
    // this only creates a promise for the async actions
    if (payload.type !== ACTION_RESTORE) {
        // Create the promise and assign the resolvers to the object.
        const deferredPromise = new Promise((resolve, reject)=>{
            resolvers = {
                resolve,
                reject
            };
        });
        startTransition(()=>{
            // we immediately notify React of the pending promise -- the resolver is attached to the action node
            // and will be called when the associated action promise resolves
            setState(deferredPromise);
        });
    }
    const newAction = {
        payload,
        next: null,
        resolve: resolvers.resolve,
        reject: resolvers.reject
    };
    // Check if the queue is empty
    if (actionQueue.pending === null) {
        // The queue is empty, so add the action and start it immediately
        // Mark this action as the last in the queue
        actionQueue.last = newAction;
        runAction({
            actionQueue,
            action: newAction,
            setState
        });
    } else if (payload.type === ACTION_NAVIGATE || payload.type === ACTION_RESTORE) {
        // Navigations (including back/forward) take priority over any pending actions.
        // Mark the pending action as discarded (so the state is never applied) and start the navigation action immediately.
        actionQueue.pending.discarded = true;
        // The rest of the current queue should still execute after this navigation.
        // (Note that it can't contain any earlier navigations, because we always put those into `actionQueue.pending` by calling `runAction`)
        newAction.next = actionQueue.pending.next;
        // if the pending action was a server action, mark the queue as needing a refresh once events are processed
        if (actionQueue.pending.payload.type === ACTION_SERVER_ACTION) {
            actionQueue.needsRefresh = true;
        }
        runAction({
            actionQueue,
            action: newAction,
            setState
        });
    } else {
        // The queue is not empty, so add the action to the end of the queue
        // It will be started by runRemainingActions after the previous action finishes
        if (actionQueue.last !== null) {
            actionQueue.last.next = newAction;
        }
        actionQueue.last = newAction;
    }
}
let globalActionQueue = null;
export function createMutableActionQueue(initialState) {
    const actionQueue = {
        state: initialState,
        dispatch: (payload, setState)=>dispatchAction(actionQueue, payload, setState),
        action: async (state, action)=>{
            const result = reducer(state, action);
            return result;
        },
        pending: null,
        last: null
    };
    if (typeof window !== 'undefined') {
        // The action queue is lazily created on hydration, but after that point
        // it doesn't change. So we can store it in a global rather than pass
        // it around everywhere via props/context.
        if (globalActionQueue !== null) {
            throw Object.defineProperty(new Error('Internal Next.js Error: createMutableActionQueue was called more ' + 'than once'), "__NEXT_ERROR_CODE", {
                value: "E624",
                enumerable: false,
                configurable: true
            });
        }
        globalActionQueue = actionQueue;
    }
    return actionQueue;
}
export function getCurrentAppRouterState() {
    return globalActionQueue !== null ? globalActionQueue.state : null;
}

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