Lesion Tracker Redesign so far

Packages/viewerbase/lib/helpers/logical.js

@@ -0,0 +1,35 @@
+Template.registerHelper('choose', function() {
+    let result;
+    _.each(_.initial(arguments, 1), function(value) {
+        return value && (result = value);
+    });
+    return result;
+});
+
+Template.registerHelper('bool', function(value) {
+    return !!value;
+});
+
+Template.registerHelper('equals', function(a, b) {
+    return a === b;
+});
+
+Template.registerHelper('not', function(value) {
+    return !value;
+});
+
+Template.registerHelper('and', function() {
+    let result = true;
+    _.each(_.initial(arguments, 1), function(value) {
+        return value || (result = false);
+    });
+    return result;
+});
+
+Template.registerHelper('or', function() {
+    let result = false;
+    _.each(_.initial(arguments, 1), function(value) {
+        return value && (result = true);
+    });
+    return result;
+});