Datatable limit change problem

<!DOCTYPE html>
<html>

  <head>
  <base href="." />
    <title>ng-bootstrap demo</title>
    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-alpha.6/css/bootstrap.min.css" />
    <script src="https://unpkg.com/zone.js@0.8.7/dist/zone.js"></script>
    <script src="https://unpkg.com/zone.js@0.8.7/dist/long-stack-trace-zone.js"></script>
    <script src="https://unpkg.com/reflect-metadata@^0.1.8/Reflect.js"></script>
    <script src="https://unpkg.com/systemjs@^0.19.40/dist/system.js"></script>
    <script src="config.js"></script>
    <script>
    System.import('app').catch(console.error.bind(console));
</script>
  </head>

  <body>
  <my-grid>loading...</my-grid>
  </body>

</html>

var ver = {
    ng: '4.0.3'
  };
  
  System.config({
  //use typescript for compilation
  transpiler: 'typescript',
  //typescript compiler options
  typescriptOptions: {
    emitDecoratorMetadata: true
  },
  paths: {
    'npm:': 'https://unpkg.com/'
  },
  map: {

    'app': './src',

    '@angular/core': 'npm:@angular/core@' + ver.ng + '/bundles/core.umd.js',
    '@angular/common': 'npm:@angular/common@' + ver.ng + '/bundles/common.umd.js',
    '@angular/compiler': 'npm:@angular/compiler@' + ver.ng + '/bundles/compiler.umd.js',
    '@angular/platform-browser': 'npm:@angular/platform-browser@' + ver.ng + '/bundles/platform-browser.umd.js',
    '@angular/platform-browser-dynamic': 'npm:@angular/platform-browser-dynamic@' + ver.ng + '/bundles/platform-browser-dynamic.umd.js',
    '@angular/http': 'npm:@angular/http@' + ver.ng + '/bundles/http.umd.js',
    '@angular/router': 'npm:@angular/router@' + ver.ng + '/bundles/router.umd.js',
    '@angular/forms': 'npm:@angular/forms@' + ver.ng + '/bundles/forms.umd.js',

    'rxjs': 'npm:rxjs@^5.0.1',
    'typescript': 'npm:typescript@2.1.5/lib/typescript.js',

    '@ng-bootstrap/ng-bootstrap': 'npm:@ng-bootstrap/ng-bootstrap@1.0.0-alpha.25/bundles/ng-bootstrap.js',
    '@swimlane/ngx-datatable': 'npm:@swimlane/ngx-datatable@9.1.0/release/index.js',
  },
  packages: {
    app: {
      main: './main.ts',
      defaultExtension: 'ts'
    },
    rxjs: {
      defaultExtension: 'js'
    }
  }
});

import {platformBrowserDynamic} from '@angular/platform-browser-dynamic';
import {AppModule} from './app';

platformBrowserDynamic().bootstrapModule(AppModule);

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { FormsModule } from '@angular/forms';
import { HttpModule } from '@angular/http';

import { NgxDatatableModule } from '@swimlane/ngx-datatable';
import { NgbModule } from '@ng-bootstrap/ng-bootstrap';

import { MyGridComponent } from './mygrid.component';

@NgModule({
  declarations: [
    MyGridComponent
  ],
  imports: [
    BrowserModule,
    FormsModule,
    HttpModule,
    NgxDatatableModule,
    NgbModule.forRoot(),
  ],
  bootstrap: [MyGridComponent]
})
export class AppModule {
}

import { Component, OnInit, Input, ViewChild } from '@angular/core';
import { DatatableComponent } from '@swimlane/ngx-datatable';

@Component({
  selector: 'my-grid',
  templateUrl: './src/mygrid.component.html'
})
export class MyGridComponent implements OnInit {
  @ViewChild(DatatableComponent) table:DatatableComponent;

  data = [];
  cols = [
    {prop: 'name'},
    {prop: 'age'}
  ];

  totalSize:number;
  pageSize:number;
  currentPage:number; // 1 based paging for ng-bootstrap

  limitOptions = [
    {
      key: '5',
      value: 5
    },
    {
      key: '10',
      value: 10
    },
    {
      key: '20',
      value: 20
    }
  ];

  constructor() {

  }

  ngOnInit() {
    this.currentPage = 1;
    this.pageSize = 10;
    this.table.limit = 10;

    this.updateData();
  }

  onPageChanged(pageNum) {
    this.currentPage = pageNum;
    this.table.offset = pageNum - 1;
  }

  onSort(event) {
    this.onPageChanged(1);
  }

  updateData() {
    let dataLength = 50 + Math.floor(Math.random() * 100);

    this.data = [];

    for (var i = 0; i < dataLength; i++) {
      this.data.push({
        name: 'name ' + (i + 1),
        age: Math.floor(Math.random() * 50)
      });
    }

    this.totalSize = this.data.length;

    // clear sorting on new data
    this.table.sorts = [];

    // reset current pagination to first page after data refresh
    this.onPageChanged(1);
  }

  onPageSizeChanged(event) {
    this.table.limit = event;
    this.onPageChanged(1);
    this.data = this.data.slice();
    console.log(event);
  }
}

<select [(ngModel)]="pageSize" (ngModelChange)="onPageSizeChanged($event)">
    <option *ngFor="let opt of limitOptions" [ngValue]="opt.value">{{opt.key}}</option>
</select> Rows per page
<br/>
<ngx-datatable
        #table
        class="material striped"
        [rows]="data"
        [columns]="cols"
        [columnMode]="'force'"
        [footerHeight]="50"
        [rowHeight]="'auto'"
        (sort)="onSort($event)">
    <ngx-datatable-footer>
        <ng-template ngx-datatable-footer-template>
            <ngb-pagination
                    #ngbPage
                    [boundaryLinks]="true"
                    [collectionSize]="totalSize"
                    [pageSize]="pageSize"
                    [page]="currentPage"
                    [maxSize]="5"
                    (pageChange)="onPageChanged($event)">
            </ngb-pagination>
        </ng-template>
    </ngx-datatable-footer>
</ngx-datatable>