fails if undefined value is passed

[yoshuawuyts]

The following code returns an error:

var foo = undefined
hx`<h1>${foo}</h1>`

Uncaught TypeError: Cannot read property '0' of undefined

I think there are two ways of resolving this:

1. null and undefined values are treated as blank (e.g. yield <h1></h1>)
2. null and undefined values are treated as errors that should never be rendered, and an appropriate error message is thrown

I think my preference goes out to option 1, as visual quirks in UI are generally non-critical; though perhaps there are good arguments for option 2 which is probably more correct.

[almost]

I'd definitely vote for 1, that allows much more natural code in some places

[ghost]

What about turning undefined and null values into the strings undefined and null?

[almost]

That to me seems much less useful. It's a very rare thing that I'd actually want the words "null" or "undefined" in my html output and in those cases I think I'd rather be explicit. But a function that maybe returns some markup or maybe returns nothing? I do that all the time!

[ghost]

Merged this suggestion into 1.1.0: now null and undefined result in an empty string. Other types get coerced to strings to avoid type errors later on.