Handlebars block helper for filtering arrays by a path.

filter-helper.js

   function filterHelper(context, options) {
        if (!options || !options.hash.where) {
            throw new Exception('Must pass <where> and <is> | <isnot> to #filter');
        }

        if (Handlebars.Utils.isFunction(context)) {
            context = context.call(this);
        }

        if (options.data) {
          var data = Handlebars.createFrame(options.data);
        }

        var newContext = context;
        var skiped = 0;
        var included = 0;
        var path = options.hash.where.split('.');
        var pathLength = path.length;

        if (Handlebars.Utils.isArray(context)) {
            newContext = context.filter(function(obj){
                var current = obj;

                for (var i = 0; i < pathLength; i++) {
                    if (current[path[i]] == undefined) {
                        current = undefined;
                    }
                    current = current[path[i]];
                }

                included++;

                if (options.hash.maxSkip && skiped >= options.hash.maxSkip) {
                    return true;
                }

                if (options.hash.max && included > options.hash.max) {
                    return false;
                }

                if (current == options.hash.is) {
                    if (current == options.hash.is) {
                        return true;
                    }
                }
                else if (options.hash.isnot) {
                    if (current != undefined && current != options.hash.isnot) {
                        return true;
                    }
                }

                included--;
                skiped++;
                return false;
            });
        }
        else {
            throw new Exception('Must pass array to #filter');
        }

        if (options.hash.as)
            data[options.hash.as] = newContext

        return options.fn(newContext[0], {data: data});
    }

loop.hbs

{{#filter posts where="featured" is=true max=1}}
    <article class="{{post_class}}">
        <header class="post-header {{#if image}} with-image" style="background-image: url({{image}}){{else}}no-cover{{/if}}">
            <h2 class="post-title"><a href="{{url}}">{{{title}}}</a></h2>
        </header>
        <section class="post-excerpt">
            <p>{{excerpt words="26"}} <a class="read-more" href="{{url}}">&raquo;</a></p>
        </section>
        <footer class="post-meta">
            {{#if author.image}}<img class="author-thumb" src="{{author.image}}" alt="{{author.name}}" nopin="nopin" />{{/if}}
            {{author}}
            {{tags prefix=" on "}}
            <time class="post-date" datetime="{{date format='YYYY-MM-DD'}}">{{date format="DD MMMM YYYY"}}</time>
        </footer>
    </article>
{{/filter}}

{{#filter posts where="featured" isnot=true as="filteredPosts" maxSkip=1}}
    {{#foreach @filteredPosts columns=3}}
        {{#if @rowStart}}
        <div class="show-3">
        {{/if}}
            <article class="column {{post_class}}">
                <header class="post-header {{#if image}} with-image" style="background-image: url({{image}}){{else}}no-cover{{/if}}">
                    <h2 class="post-title"><a href="{{url}}">{{{title}}}</a></h2>
                </header>
                <section class="post-excerpt">
                    <p>{{excerpt words="26"}} <a class="read-more" href="{{url}}">&raquo;</a></p>
                </section>
                <footer class="post-meta">
                    {{#if author.image}}<img class="author-thumb" src="{{author.image}}" alt="{{author.name}}" nopin="nopin" />{{/if}}
                    {{author}}
                    {{tags prefix=" on "}}
                    <time class="post-date" datetime="{{date format='YYYY-MM-DD'}}">{{date format="DD MMMM YYYY"}}</time>
                </footer>
            </article>
        {{#if @rowEnd}}
        </div>
        {{/if}}
    {{/foreach}}
{{/filter}}