Custom component property check

How-to Discussions
1

Hi,

How to check custom component propert value is empty?

<Circle ux:Class="LinkedCircle"   Width="40" Height="40" Margin="2" Url="" Visibility="Visible">
        <string ux:Property="Url"  />
        <JavaScript>
            var Observable = require('FuseJS/Observable');


            module.exports={
                isEmpty: (!this.Url || this.Url.length==0) //here is check empty
            };
        </JavaScript>
         <WhileTrue Value="{isEmpty}">
             <Change this.Visibility="Collapsed" />
         </WhileTrue>
        <Clicked>
            <LaunchUri Uri="{Property this.Url}" />
         </Clicked>
        <WhilePressed>
            <Scale Factor="0.8" Duration=".15" Easing="CubicInOut" />        </WhilePressed>
</Circle>
2

You can use the map function on the Url observable. Have a look at this example:

<Panel ux:Class="MyComponent" Color="#e00" ux:Name="self">
    <string ux:Property="Url" />
    <JavaScript>
        var Observable = require('FuseJS/Observable');
        var url_empty = this.Url.map(function (url) {
            var empty = true;
            if (url)
                empty = url.length == 0;
            return empty;
        });

        module.exports = {
            url_empty:url_empty
        };

    </JavaScript>
    <WhileFalse Value="{url_empty}">
        <Change Target="self.Color" Value="#0e0" />
    </WhileFalse>
</Panel>