nil coalescing ?

[daniel-torok]

Can we do nil coalescing?

For example I have the following template:

{{ $ds := datasource "ds" }}
foo:
  bar: {{ $ds.nonExisting | coalesce 1 }}

With nonExisting: 2 in ds it would produce bar: 2.
Without nonExisting in ds it would produce bar: 1.

[hairyhenderson]

(I've moved this to a discussion, as this isn't an issue so much as a question)

@daniel-torok There is a way to accomplish this, though not in a way that's quite so compact. This can, however, be accomplished with an if condition.

One issue is that if you try to reference a missing key, gomplate will error - this is by design as gomplate treats missing keys as errors (see #310 for some discussion on this). To avoid this, you'll want to use has.

Here's an example:

{{ $ds := datasource "ds" }}
foo:
  bar: {{ if has $ds "nonExisting" }}{{ $ds.nonExisting }}{{ else }}1{{end}}

Alternately, if the key does exist, but you want to test whether it's false, you could look at the ternary function. However in that case, IMO just using if would be more readable anyway.

[daniel-torok]

Thank you for your response!