How to use the dexie.defineClass function in dexie

var NODE_TIMEOUT = 20000, // 20 seconds before local db instances are timed out. This is so that old changes can be deleted when not needed and to garbage collect old _syncNodes objects.
        HIBERNATE_GRACE_PERIOD = 20000, // 20 seconds
        // LOCAL_POLL: The time to wait before polling local db for changes and cleaning up old nodes. 
        // Polling for changes is a fallback only needed in certain circomstances (when the onstorage event doesnt reach all listeners - when different browser windows doesnt share the same process)
        LOCAL_POLL = 2000, // 1 second. In real-world there will be this value + the time it takes to poll().
        CREATE = 1,
        UPDATE = 2,
        DELETE = 3;

    var localStorage = Observable.localStorageImpl;

    /** class SyncNode
        *
        * Object contained in the _syncNodes table.
        */
    var SyncNode = Dexie.defineClass({
        //id: Number,
        myRevision: Number,
        type: String, // "local" or "remote"
        lastHeartBeat: Number,
        deleteTimeStamp: Number, // In case lastHeartBeat is too old, a value of now + HIBERNATE_GRACE_PERIOD will be set here. If reached before node wakes up, node will be deleted.
        url: String, // Only applicable for "remote" nodes. Only used in Dexie.Syncable.
        isMaster: Number, // 1 if true. Not using Boolean because it's not possible to index Booleans in IE implementation of IDB.

        // Below properties should be extended in Dexie.Syncable. Not here. They apply to remote nodes only (type == "remote"):
        syncProtocol: String, // Tells which implementation of ISyncProtocol to use for remote syncing. 
        syncContext: null,
        syncOptions: Object,
        connected: false, // FIXTHIS: Remove! Replace with status.
        status: Number,
        appliedRemoteRevision: null,
        remoteBaseRevisions: [{ local: Number, remote: null }],

import Dexie from 'dexie';

var global = self;

/** class DatabaseChange
    *
    *  Object contained by the _changes table.
    */
var DatabaseChange = Dexie.defineClass({
    rev: Number, // Auto-incremented primary key
    source: String, // Optional source creating the change. Set if transaction.source was set when doing the operation.
    table: String, // Table name
    key: Object, // Primary key. Any type.
    type: Number, // 1 = CREATE, 2 = UPDATE, 3 = DELETE
    obj: Object, // CREATE: obj contains the object created.
    mods: Object, // UPDATE: mods contains the modifications made to the object.
    oldObj: Object // DELETE: oldObj contains the object deleted. UPDATE: oldObj contains the old object before updates applied.
});

// Import some usable helper functions
var override = Dexie.override;
var Promise = Dexie.Promise;
var browserIsShuttingDown = false;

function Observable(db) {

var NODE_TIMEOUT = 20000, // 20 seconds before local db instances are timed out. This is so that old changes can be deleted when not needed and to garbage collect old _syncNodes objects.
        HIBERNATE_GRACE_PERIOD = 20000, // 20 seconds
        // LOCAL_POLL: The time to wait before polling local db for changes and cleaning up old nodes. 
        // Polling for changes is a fallback only needed in certain circomstances (when the onstorage event doesnt reach all listeners - when different browser windows doesnt share the same process)
        LOCAL_POLL = 2000, // 1 second. In real-world there will be this value + the time it takes to poll().
        CREATE = 1,
        UPDATE = 2,
        DELETE = 3;

    var localStorage = Observable.localStorageImpl;

    /** class SyncNode
        *
        * Object contained in the _syncNodes table.
        */
    var SyncNode = Dexie.defineClass({
        //id: Number,
        myRevision: Number,
        type: String, // "local" or "remote"
        lastHeartBeat: Number,
        deleteTimeStamp: Number, // In case lastHeartBeat is too old, a value of now + HIBERNATE_GRACE_PERIOD will be set here. If reached before node wakes up, node will be deleted.
        url: String, // Only applicable for "remote" nodes. Only used in Dexie.Syncable.
        isMaster: Number, // 1 if true. Not using Boolean because it's not possible to index Booleans in IE implementation of IDB.

        // Below properties should be extended in Dexie.Syncable. Not here. They apply to remote nodes only (type == "remote"):
        syncProtocol: String, // Tells which implementation of ISyncProtocol to use for remote syncing. 
        syncContext: null,
        syncOptions: Object,
        connected: false, // FIXTHIS: Remove! Replace with status.
        status: Number,
        appliedRemoteRevision: null,
        remoteBaseRevisions: [{ local: Number, remote: null }],

*
 * version: {version} Alpha, {date}
 *
 * Disclaimber: This addon is in alpha status meaning that
 * its API and behavior may change.
 *
 */
import Dexie from 'dexie';

var global = self;

/** class DatabaseChange
    *
    *  Object contained by the _changes table.
    */
var DatabaseChange = Dexie.defineClass({
    rev: Number, // Auto-incremented primary key
    source: String, // Optional source creating the change. Set if transaction.source was set when doing the operation.
    table: String, // Table name
    key: Object, // Primary key. Any type.
    type: Number, // 1 = CREATE, 2 = UPDATE, 3 = DELETE
    obj: Object, // CREATE: obj contains the object created.
    mods: Object, // UPDATE: mods contains the modifications made to the object.
    oldObj: Object // DELETE: oldObj contains the object deleted. UPDATE: oldObj contains the old object before updates applied.
});


// Import some usable helper functions
var override = Dexie.override;
var Promise = Dexie.Promise;
var browserIsShuttingDown = false;

// 20 seconds
    // LOCAL_POLL: The time to wait before polling local db for changes and cleaning up old nodes.
    // Polling for changes is a fallback only needed in certain circomstances (when the onstorage event doesnt reach all listeners - when different browser windows doesnt share the same process)
    LOCAL_POLL = 2000,
        // 1 second. In real-world there will be this value + the time it takes to poll().
    CREATE = 1,
        UPDATE = 2,
        DELETE = 3;

    var localStorage = Observable.localStorageImpl;

    /** class SyncNode
        *
        * Object contained in the _syncNodes table.
        */
    var SyncNode = Dexie.defineClass({
        //id: Number,
        myRevision: Number,
        type: String, // "local" or "remote"
        lastHeartBeat: Number,
        deleteTimeStamp: Number, // In case lastHeartBeat is too old, a value of now + HIBERNATE_GRACE_PERIOD will be set here. If reached before node wakes up, node will be deleted.
        url: String, // Only applicable for "remote" nodes. Only used in Dexie.Syncable.
        isMaster: Number, // 1 if true. Not using Boolean because it's not possible to index Booleans in IE implementation of IDB.

        // Below properties should be extended in Dexie.Syncable. Not here. They apply to remote nodes only (type == "remote"):
        syncProtocol: String, // Tells which implementation of ISyncProtocol to use for remote syncing.
        syncContext: null,
        syncOptions: Object,
        connected: false, // FIXTHIS: Remove! Replace with status.
        status: Number,
        appliedRemoteRevision: null,
        remoteBaseRevisions: [{ local: Number, remote: null }],

*
 * version: {version} Alpha, {date}
 *
 * Disclaimber: This addon is in alpha status meaning that
 * its API and behavior may change.
 *
 */
import Dexie from 'dexie';

var global = self;

/** class DatabaseChange
    *
    *  Object contained by the _changes table.
    */
var DatabaseChange = Dexie.defineClass({
    rev: Number, // Auto-incremented primary key
    source: String, // Optional source creating the change. Set if transaction.source was set when doing the operation.
    table: String, // Table name
    key: Object, // Primary key. Any type.
    type: Number, // 1 = CREATE, 2 = UPDATE, 3 = DELETE
    obj: Object, // CREATE: obj contains the object created.
    mods: Object, // UPDATE: mods contains the modifications made to the object.
    oldObj: Object // DELETE: oldObj contains the object deleted. UPDATE: oldObj contains the old object before updates applied.
});


// Import some usable helper functions
var override = Dexie.override;
var Promise = Dexie.Promise;
var browserIsShuttingDown = false;