CODEWITHSUNDEEP
knockout.js
Ominus
Ominus

Reputation: 5721

knockout.js change visible status based on if array is empty or not

I want to be able to have a table show only if there are items in an array. I have simplified down my needs to this jsfiddle example.

JS:

var view_model = {
    lines: ko.observableArray([
        {
        content: 'one'},
    {
        content: 'two'},
    {
        content: 'three'},
    {
        content: 'four'},
        ]),
    remove: function(data) {
        view_model.lines.remove(data);
    }
};

ko.applyBindings(view_model);

HTML:

<span data-bind="visible:lines">Lines Exist</span> 
<ul data-bind='foreach:lines'>
    <li>
        <button data-bind="click:$parent.remove">
            Remove
        </button>
        <span data-bind="text:content"></span>
    </li>
</ul>

Basically I have a web app where lines can be removed from table. If array.length == 0, I want to hide the entire table.

Upvotes: 29

Views: 35102

Answers (4)

saber tabatabaee yazdi
saber tabatabaee yazdi

Reputation: 4959

if you want to show message or image like this jsfiddle example 

<div data-bind="visible:lines().length">
    You will see this message only when "lines" holds a true value.
    <img src=""/>
</div>

if you want to hide message when table lines datas appeared successfully 

<div data-bind="visible: !lines().length">
    You will see this message only when "lines" holds a false value.
    <img src=""/>
</div>

Upvotes: 0

Johan Frick
Johan Frick

Reputation: 1124

It is considered bad practice to add logic to the html template. I suggest this solution:

<div data-bind="with: lines">     
    <span data-bind="if: length">Lines Exist</span>
    <ul data-bind='foreach:$data'>
        <li>
            <button data-bind="click:$parent.remove">
                Remove
            </button>
            <span data-bind="text:content"></span>
        </li>
    </ul>
</div>

Upvotes: 0

Lgiro
Lgiro

Reputation: 772

Another solution, slight variation on your original attempt:

<div data-bind="visible:lines().length">
    <span>Lines Exist</span> 
    <p>Here is my table</p>
    <ul data-bind='foreach:lines'>
        <li>
            <button data-bind="click:$parent.remove">
                Remove
            </button>
            <span data-bind="text:content"></span>
        </li>
    </ul>
</div>

Upvotes: 8

John Papa
John Papa

Reputation: 22338

You can do this in several ways. The fiddle below uses the containerless bindings to hide the entire table if the lines array has no entries.

http://jsfiddle.net/johnpapa/WLapt/4/

<span data-bind="visible:lines">Lines Exist</span> 
<!-- ko if: lines().length > 0-->
<p>Here is my table</p>
<ul data-bind='foreach:lines'>
    <li>
        <button data-bind="click:$parent.remove">
            Remove
        </button>
        <span data-bind="text:content"></span>
    </li>
</ul>
<!-- /ko -->​

Upvotes: 47

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