Handlebars helper: #each-paginate

handlebars-helper-each-paginate.js

var Handlebars = require('handlebars');

// with `ctx` = [a, b, c, d, e, f, g, h] and `count` = 3
// will iterate over [[a, b, c], [d, e, f], [g, h]]
Handlebars.registerHelper('each-paginate', function(context, opts) {
  // similar to Python's range
  var range = n => Array.from(new Array(n).keys()); 
  
  // items per page and page count - defaults to a single page with all the items
  var perPage = opts.hash.perPage || context.length;
  var pageCount = Math.ceil(context.length / perPage);
  
  // array of arrays
  var pages = range(pageCount).map(i => context.slice(i*perPage, (i+1)*perPage));
  
  return Handlebars.helpers.each(pages, opts);
});

/*
Example :

{{#each-paginate products perPage=4}}
<div class="row">
    {{#each this}}
    <article class="product">
        <h4 class="product-title">{{name}}</h4>
        <p class="benefits turquoise">{{info}}</p>
        <p class="benefits-description">{{desc}}</p>
    </article>
    {{/each}}
</div>
{{/each-paginate}}

*/