Call JavaScript function from JsRender

I have a JsRender template. When template is rendering I want to call a JavaScript function to manipulate some data.

Here is my JsRender template.

<tr class="template-download">
   <td class="size">
        <span>{{:size}}</span>
   </td>
</tr>

Now I want to pass :size value to JavaScript function and get the return value. So I can show return value instead of :size value.

My JavaScript function is

function getSize(size) {
    var megabytes = size / (1024 * 1024);
    return megabytes.toFixed(2) + "MB";
}

How can I do this?

You can do this by using a helper function. When you call render, you can define and pass a helper function 'into' your template:

$("#tmpl").render(data, {
    getSize: function(size) {
        var megabytes = size / (1024 * 1024);
        return megabytes.toFixed(2) + "MB";
    }
});

Then, in your template, you call the helper function like this:

<tr class="template-download">
   <td class="size">
        <span>{{:size}} {{:~getSize(size)}} </span>
   </td>
</tr>

I've made a couple of assumptions about how your template is being used, but this should get you going.

This article has a section related to helper functions, and @BorisMoore has a number of good examples on his jsViews site.