Making a Handlebars partial behave a little more like partials in erb.

README.md

Props to @keeganstreet for the idea around using JSON passed through as a string. This also allows you to declare the partial name, in a previous partial and load it using a string instead of relying on the name by itself. See the more detailed example (last file) for how this works.

handlebars-helper-partial.hbs

Handlebars.registerHelper('partial', function(name, vars, options) {
    var partial = Handlebars.partials[name],
        locals = {};

    if (!partial) {
        console.error('Partial not loaded.');
        return 'Partial not loaded.';
    }

    if (!vars) {
        locals = this;
    }

    if (typeof (vars) === 'object') {
        locals.locals = vars;
    } else if (typeof (vars) === 'string') {
        try {
            locals.locals = JSON.parse(vars);
        } catch (e) {}
    }

    return new Handlebars.SafeString(Handlebars.compile(partial)(locals));
});

load-modules.hbs

{{#with locals}}
<ul class="modules">
    {{#each modules}}
        <li>{{partial partial locals}}</li>
    {{/each}}
</ul>
{{/with}}

module.hbs

{{#with locals}}
<div class="module">
    <h2>{{title}}</h2>
    <p>{{description}}</p>
</div>
{{/with}}

usage.hbs

<!-- START simple usage -->
{{partial 'module' '{
    "title": "Example title"
    "description": "Some description text lorem ipsum
}'}}
<!-- END simple usage -->

<!-- START complex usage -->
{{partial 'load-modules' '{
    "modules": [
        {
            "partial": "module",
            "locals": {
                "title": "Title 1",
                "description": "Description 1"
            }
        },
        {
            "partial": "module",
            "locals": {
                "title": "Title 2",
                "description": "Description 2"
            }
        },
        {
            "partial": "module",
            "locals": {
                "title": "Title 3",
                "description": "Description 3"
            }
        }
    ]
}'}}
<!-- END complex usage -->