class attribute doesn't work as expected

[AvremelM]

There are some issues with specifying (or not specifying) a class attribute on an {{fa-icon}} component. (This usage is demonstrated in the README, and is presumably supported, since it kinda works).

For example:

{{fa-icon "map"}}
{{fa-icon "map" class=""}}
{{fa-icon "map" class="grey"}}

results in

<svg ... class="svg-inline--fa fa-map fa-w-18  undefined ember-view"></svg>
<svg ... class="svg-inline--fa fa-map fa-w-18   ember-view"></svg>
<svg ... class="grey svg-inline--fa fa-map fa-w-18 grey grey ember-view"></svg>

This is with default setup in version 0.1.9

[robclancy]

I don't even get "undefined" with what I just did, I get an error calling split on undefined. It's because of the way they workout the class names.

Fails
<FaIcon @icon={{icon}} @class="{{unless badge (concat 'u-c-' color '5'}}" />

Works
<FaIcon @icon={{icon}} @class="{{unless badge (concat 'u-c-' color '5') ''}}" />

[sarus]

Ran into this issue as well:

Fails with split on undefined error:

           {{fa-icon "circle"
                     class=iconClass
                     fixedWidth=true}}

Works:

           {{fa-icon "circle"
                     class=(concat iconClass "")
                     fixedWidth=true}}

[acorncom]

Likely fixed by #120