Q:

EasySearch meteor

is it possible to change the button loadmore of the easySearch search package by a spinner? Giving you style?
According to the documentation can give the style, I have tried to make it work, but so far I have not been successful.
{{> EasySearch.LoadMore index=myIndex content="Load more content"}}

Parameters
content: The content of the button attributes: Object with the button
  attributes (e.g. { class: "load-more-button" })
  count: Number of documents to load

A:

Unfortunately, you will not be able to change from a 'button' to a 'spinner' because the EasySearch.LoadMore component literally renders an HTML button element (see below taken from the EasySearch source).
<template name="EasySearch.LoadMore">
    {{#if moreDocuments}}
        <button {{attributes}}>{{content}}</button>
    {{/if}}
</template>

Even though you cannot change to a spinner, you can at least style the 'button' using the attributes argument (which you mentioned in your question).  To do this, just pass an object that contains a class property.  Since you cannot define object literals in spacebars, you will have to create a template helper to do this (as I have shown in the below example).
Template.mySearch.helpers({
  loadMoreAttributes: function() {
    return {
      class: "load-more-button"
    }
  },
});

Then use your helper in your template like this.
{{> EasySearch.LoadMore index=myIndex content="Load more content" attributes=loadMoreAttributes}}

This will give your "load more" button a css class of load-more-button.  Then you can just style it in css like the example below.  Obviously, you will use the styling that you want...this is purely for example.
.load-more-button {
    background-color: #4CAF50; /* Green */
    border: none;
    color: white;
    padding: 15px 32px;
    text-align: center;
    text-decoration: none;
    display: inline-block;
    font-size: 16px;
}

