Document how to use array outputs in job conditionals

[pauleustice]

Is your feature request related to a problem? Please describe.

I find that the GitHub documentation around fromJSON/toJSON is not very clear, and it's not always obvious how to use data from github-script steps. I am especially stuck on how to use array outputs to conditionally run steps, which has led to lots of frustration. There is currently no documentation about how to do this, although I'd be happy to contribute some if I knew the answer!

For example (non-working):

- name: Some step
  if: ${{ steps.setArrayOutputs.outputs.jsArray.length > 0 }}

I have tried everything I can think of to get this to work, please see this workflow containing multiple tests (and associated workflow run).

Describe the solution you'd like

Better documentation on how to use data output from the github-script action.

[pauleustice]

I think I now understand that you can't access length of arrays in the GH context, so please ignore

[joshmgross]

@pauleustice if you still needed to do this, you could potentially use something like:

- name: Some step
  if: ${{ steps.setArrayOutputs.outputs.jsArray }}

or

- name: Some step
  if: ${{ toJSON(steps.setArrayOutputs.outputs.jsArray) != "[]" }}

I think either of those should work, but I haven't validated them.