@ima/core/dist/esm/client/page/state/PageStateManagerImpl.js

IMA.js framework for isomorphic javascript application

import { PageStateManager } from './PageStateManager';
import { StateEvents } from './StateEvents';
import { Dispatcher } from '../../event/Dispatcher';
const MAX_HISTORY_LIMIT = 10;
/**
 * The implementation of the {@link PageStateManager} interface.
 */ export class PageStateManagerImpl extends PageStateManager {
    _cursor = -1;
    _dispatcher;
    _ongoingTransaction = false;
    _statePatchQueue = [];
    _states = [];
    static get $dependencies() {
        return [
            Dispatcher
        ];
    }
    /**
   * Initializes the page state manager.
   *
   * @param {Dispatcher} dispatcher Dispatcher fires events to app.
   */ constructor(dispatcher){
        super();
        this._dispatcher = dispatcher;
    }
    /**
   * @inheritDoc
   */ clear() {
        this._states = [];
        this._cursor = -1;
        this.cancelTransaction();
    }
    /**
   * @inheritDoc
   */ setState(patchState) {
        if (this._ongoingTransaction) {
            return this._statePatchQueue.push(patchState);
        }
        const oldState = this.getState();
        const newState = Object.assign({}, this.getState(), patchState);
        if (this._dispatcher) {
            this._dispatcher.fire(StateEvents.BEFORE_CHANGE_STATE, {
                newState,
                oldState,
                patchState
            });
        }
        this._eraseExcessHistory();
        this._pushToHistory(newState);
        this._callOnChangeCallback(newState);
    }
    /**
   * @inheritDoc
   */ getState() {
        return this._states[this._cursor] || {};
    }
    /**
   * @inheritDoc
   */ getAllStates() {
        return this._states;
    }
    /**
   * @inheritDoc
   */ getTransactionStatePatches() {
        return this._statePatchQueue;
    }
    /**
   * @inheritDoc
   */ beginTransaction() {
        if ($Debug && this._ongoingTransaction) {
            console.warn('ima.core.page.state.PageStateManagerImpl.beginTransaction():' + 'Another state transaction is already in progress. Check you workflow.' + 'These uncommitted state changes will be lost:', this._statePatchQueue);
        }
        this._ongoingTransaction = true;
        this._statePatchQueue = [];
    }
    /**
   * @inheritDoc
   */ commitTransaction() {
        if ($Debug && !this._ongoingTransaction) {
            console.warn('ima.core.page.state.PageStateManagerImpl.commitTransaction():' + 'No transaction is in progress. Check you workflow.');
        }
        if (this._statePatchQueue.length === 0) {
            this._ongoingTransaction = false;
            return;
        }
        const finalPatch = Object.assign({}, ...this._statePatchQueue);
        this._ongoingTransaction = false;
        this._statePatchQueue = [];
        this.setState(finalPatch);
    }
    /**
   * @inheritDoc
   */ cancelTransaction() {
        this._ongoingTransaction = false;
        this._statePatchQueue = [];
    }
    /**
   * Erase the oldest state from storage only if it exceed max
   * defined size of history.
   */ _eraseExcessHistory() {
        if (this._states.length > MAX_HISTORY_LIMIT) {
            this._states.shift();
            this._cursor -= 1;
        }
    }
    /**
   * Push new state to history storage.
   */ _pushToHistory(newState) {
        this._states.push(newState);
        this._cursor += 1;
    }
    /**
   * Call registered callback function on (@link onChange) with newState.
   */ _callOnChangeCallback(newState) {
        if (this.onChange && typeof this.onChange === 'function') {
            this.onChange(newState);
        }
        if (this._dispatcher) {
            this._dispatcher.fire(StateEvents.AFTER_CHANGE_STATE, {
                newState
            });
        }
    }
}

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