Handlebars custom helper

I have been trying to make a custom handlebars helper

This is the helper file

 * Handlebars helpers.
 * These functions are to be used in handlebars templates.
 * @class Handlebars.helpers
 * @singleton
(function (app) {
    app.events.on("app:init", function () {

         * convert a string to upper case
        Handlebars.registerHelper('tristate', function (value) {
            let markup = '';
            switch (value) {
                case '1':
                    markup = "CHECKED";
                case '2':
                    markup = "indeterminate=1";
                    markup = "";
            return markup;


Then I have my JSGroupings file

//Loop through the groupings to find grouping file you want to append to
foreach ($js_groupings as $key => $groupings) {
	foreach ($groupings as $file => $target) {
		//if the target grouping is found
		if ($target == 'include/javascript/sugar_grp7.min.js') {
			//append the custom JavaScript file
			$js_groupings[$key]['custom/javascript/jquery.tristate.js'] = 'include/javascript/sugar_grp7.min.js';
			$js_groupings[$key]['custom/javascript/handleBar-helpers.js'] = 'include/javascript/sugar_grp7.min.js';

And this is in the HBS file
<input id={{this.id}} type="checkbox" checkedvalue="1" uncheckedvalue="0"
    indeterminatevalue="2" class="row-checkbox" data-name="tristate"
    data-populated-row="{{this.populated_row}}" {{tristate this.checked}}"/>

It never seems to run the helper at all.  I have cleared the cache/, run the repairs, verified that the JS is where it should be in the sugar_grp7.min.js file. 

I also cant find where the {{log this}} is logging to.  Its not the console or the Sugar log file.