Expose {{concat}} helper publicly.

[rwjblue]

No description provided.

[mmun]

Seems bad to call it concat since that's not what it is in JS... It should be join if anything. Arguably it would take an array instead of positional args. What's the point of making this public?

[rwjblue]

Seems bad to call it concat since that's not what it is in JS

I can remove the separator (which would make it a proper concat instead of a join + separator).

What's the point of making this public?

It is a very commonly needed helper, that many folks end up writing themselves. With angle-bracket component invocation this is much less needed, but until angle-bracket invocation is ready to go I would like to bake this in.

One specific example:

<label for="{{elementId}}-input">{{label}}</label>
{{input id=(concat elementId '-input') value=value}}

Another example #11263:

{{! this is deprecated }}
{{foo-bar classBinding=":truthy isStuff"}}

{{! this is how we silence the deprecation internally }}
{{foo-bar class=(-concat "truthy" (if isStuff "is-stuff") separator=" ")}}

As far as I can tell, it is not possible for users to satisfy this deprecation notice (I actually think we should disable the deprecation until angle bracket invocation is a bit better) without either writing your own concat helper or using the private one.

[mmun]

I'd rather write (add elementId '-input') in the first case, which is what you'd write in JS. concat is fine though.

For the second case, assuming we don't deal with the deprecation another way, I'd rather have a classes helper that deals with spaces nicely. An Interpolation helper would be fine too (interpolate "truthy ${}" (if isStuff "is-stuff")). (fmt might be better).

[rwjblue]

Updated to remove separator.

[rwjblue]

rebased

[mmun]

👍