ember.js - helper returning an object not scalar value expected -

thought i'd create if-then-else helper looks this:

import ember 'ember'; export function ifthenelse(param, iftrue, iffalse=null) {   return boolean(param) ? iftrue : iffalse; }  export default ember.helper.helper(ifthenelse); 

and when using component can following:

{{my-nifty-component class=(if-then-else pigshavewings 'wake-up' 'good-answer') }} 

well problem i'm having helper not helpful , html/dom result is:

<div class="[object object] ember-view"></div> 

can please me helper?

in modern versions of ember helper function gets 1 parameter , parameter array of parameters, passed helper. need rewrite helper as

import ember 'ember';  export function ifthenelse([param, iftrue, iffalse]) {   return boolean(param) ? iftrue : iffalse || null; }  export default ember.helper.helper(ifthenelse);