Get I.T. Going: Lazy loading in koGrid

Below is the code for implementing Lazy loading in koGrid. Here is a working plunker. You can download the code from here.
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    <title>Lazy loading in koGrid</title>
    <link href="KoGrid.css" rel="stylesheet" type="text/css">
 
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.8.0/jquery.min.js"></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/knockout/3.2.0/knockout-debug.js" type="text/javascript"></script>
    <script src="koGrid-2.1.1.debug.js" type="text/javascript"></script>
    <style>
        .gridStyle {
            border: 1px solid rgb(212,212,212);
            width: 600px;
            height: 300px;
        }
    </style>
    <script>
        function pagingVm() {
            var self = this;
            this.myData = ko.observableArray([]);
 
            this.filterOptions = {
                filterText: ko.observable(""),
                useExternalFilter: true
            };
 
            this.pagingOptions = {
                pageSizes: ko.observableArray([10, 20]),
                pageSize: ko.observable(10),
                totalServerItems: ko.observable(0),
                currentPage: ko.observable(1)
            };
 
            this.setPagingData = function (data, page, pageSize) {
                var pagedData = self.myData();
 
                var newData = data.slice((page - 1) * pageSize, page * pageSize);
                for (var i = 0; i < newData.length; i++) {
                    pagedData.push(newData[i]);
                }
                self.myData(pagedData);
                self.pagingOptions.totalServerItems(data.length);
            };
 
            this.getPagedDataAsync = function (pageSize, page, searchText) {
                setTimeout(function () {
                    var data;
                    if (searchText) {
                        var ft = searchText.toLowerCase();
                        data = largeLoad.filter(function (item) {
                            return JSON.stringify(item).toLowerCase().indexOf(ft) != -1;
                        });
                        self.setPagingData(data, page, pageSize);
                    } else {
                        self.setPagingData(largeLoad, page, pageSize);
                    }
                }, 100);
            };
 
            self.filterOptions.filterText.subscribe(function (data) {
                self.getPagedDataAsync(self.pagingOptions.pageSize(), self.pagingOptions.currentPage(), self.filterOptions.filterText());
            });
 
            self.pagingOptions.pageSizes.subscribe(function (data) {
                self.getPagedDataAsync(self.pagingOptions.pageSize(), self.pagingOptions.currentPage(), self.filterOptions.filterText());
            });
            self.pagingOptions.pageSize.subscribe(function (data) {
                self.getPagedDataAsync(self.pagingOptions.pageSize(), self.pagingOptions.currentPage(), self.filterOptions.filterText());
            });
            
            self.pagingOptions.currentPage.subscribe(function (data) {
                self.getPagedDataAsync(self.pagingOptions.pageSize(), self.pagingOptions.currentPage(), self.filterOptions.filterText());
            });
 
            self.getPagedDataAsync(self.pagingOptions.pageSize(), self.pagingOptions.currentPage());
 
            this.gridOptions = {
                data: self.myData,
                columnDefs: [{ field: "name", displayName: "name" },
                            { field: "allowance", displayName: "allowance" },
                            { field: "paid", displayName: "paid" }],
                enablePaging: false,
                pagingOptions: self.pagingOptions,
                filterOptions: self.filterOptions,
                displaySelectionCheckbox: false,
                //footerVisible: false
                headerRowHeight: 40,
                rowHeight: 35,
                canSelectRows: false
            };
        };
        $(document).ready(function () {
            vm = new pagingVm();
            ko.applyBindings(vm);
 
            $('.kgViewport').scroll(function () {
                var div = $(this);
                if (div[0].scrollHeight - div.scrollTop() <= div.height()) {
                    vm.pagingOptions.currentPage(vm.pagingOptions.currentPage() + 1);
                }
            });
 
        });
    </script>
 
 
 
 
 
    <div class="gridStyle" data-bind="koGrid: gridOptions">
</div>
<script>
        var largeLoad = [{ "name": "Moroni", "allowance": 505050505050505050, "paid": true },
        { "name": "Tiancum", "allowance": 53, "paid": false },
        { "name": "Jacob", "allowance": 27, "paid": false },
        { "name": "Nephi", "allowance": 29, "paid": false },
        { "name": "Enos", "allowance": 34, "paid": false },
        { "name": "Ether", "allowance": 42, "paid": false },
        { "name": "Alma", "allowance": 43, "paid": true },
        { "name": "Jared", "allowance": 21, "paid": true },
        { "name": "Moroni2", "allowance": 50, "paid": true },
        { "name": "Tiancum2", "allowance": 53, "paid": false },
        { "name": "Jacob2", "allowance": 27, "paid": false },
        { "name": "Nephi2", "allowance": 29, "paid": false },
        { "name": "Enos2", "allowance": 34, "paid": false },
        { "name": "Ether2", "allowance": 42, "paid": false },
        { "name": "Alma2", "allowance": 43, "paid": true },
        { "name": "Jared2", "allowance": 21, "paid": true },
        { "name": "Moroni3", "allowance": 50, "paid": true },
        { "name": "Tiancum3", "allowance": 53, "paid": false },
        { "name": "Jacob3", "allowance": 27, "paid": false },
        { "name": "Nephi3", "allowance": 29, "paid": false },
        { "name": "Enos3", "allowance": 34, "paid": false },
        { "name": "Ether3", "allowance": 42, "paid": false },
        { "name": "Alma3", "allowance": 43, "paid": true },
        { "name": "Jared3", "allowance": 21, "paid": true },
        { "name": "Moroni4", "allowance": 50, "paid": true },
        { "name": "Tiancum4", "allowance": 53, "paid": false },
        { "name": "Jacob4", "allowance": 27, "paid": false },
        { "name": "Nephi4", "allowance": 29, "paid": false },
        { "name": "Enos4", "allowance": 34, "paid": false },
        { "name": "Ether4", "allowance": 42, "paid": false },
        { "name": "Alma4", "allowance": 43, "paid": true },
        { "name": "Jared4", "allowance": 21, "paid": true },
        { "name": "Moroni5", "allowance": 50, "paid": true },
        { "name": "Tiancum5", "allowance": 53, "paid": false },
        { "name": "Jacob5", "allowance": 27, "paid": false },
        { "name": "Nephi5", "allowance": 29, "paid": false },
        { "name": "Enos5", "allowance": 34, "paid": false },
        { "name": "Ether5", "allowance": 42, "paid": false },
        { "name": "Alma5", "allowance": 43, "paid": true },
        { "name": "Jared5", "allowance": 21, "paid": true }];
    </script>
Here I have modified the example given on koGrid examples page for server side paging, but to get the real advantage of on-demand loading you need to fetch paged and filtered data from the server itself. For that you can take help from my another post on server side paging in koGrid and you might need to update the "getPagedDataAsync" function in above code accordingly.
Get I.T. Going

Lazy loading in koGrid

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