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knockoutjs comparing the current row element with the previous row element.

Gautam Ramesh12130-Apr-2023

knockoutjs comparing the current row element with the previous row element.

javascriptknockout.js 
Updated on 20-Nov-2023
Gautam Ramesh

Gautam Ramesh

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I am Gautam Ramesh from Uttar Pradesh. Have completed my B. Tech. course from MNNIT campus Prayagraj in 2022. I have good knowledge of computer networking.

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1 Answers

Aryan Kumar

Aryan Kumar

20-Nov-2023

In Knockout.js, you can compare the current row element with the previous row element by utilizing the foreach binding and the $index context variable. Here's an example of how you can achieve this:

Suppose you have an observable array in your view model, and you're using the foreach binding to iterate over the array. You can use the $index context variable to compare the current row with the previous one.

HTML:

<div data-bind="foreach: items">
    <div>
        <span data-bind="text: name"></span>
        <!-- Add your comparison logic here using $index -->
        <span data-bind="visible: $index() > 0 && items()[$index()].name !== items()[$index() - 1].name">
            <!-- Display something if the current name is different from the previous one -->
            (Name changed)
        </span>
    </div>
</div>

JavaScript (Knockout.js):

function ViewModel() {
    var self = this;

    self.items = ko.observableArray([
        { name: 'John' },
        { name: 'Jane' },
        { name: 'John' },
        { name: 'Doe' }
    ]);
}

ko.applyBindings(new ViewModel());

In this example, the $index() function returns the index of the current iteration, and we use it to access the current and previous elements in the observable array (items). The comparison logic is placed inside the visible binding, and you can customize it based on your specific requirements.

This example assumes that the array contains objects with a property named name, and it displays a message when the name changes from one row to the next. Adjust the property names and comparison logic according to your actual data structure and requirements.

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