javicle/docs/asset_refs.md

Asset References

Most operations have a source parameter that indicates what asset is considered the primary input to that operation.

The value of source is the name of an asset, either defined in assets or as the output of a previous operation (named in the creates block).

List Assets

The split operation creates multiple assets under the same name, this is called a “list asset”, in contrast to a “singular asset” that only refers to one file.

If you want to reference a specific file within a list asset, use square bracket notation:

some_list_asset[0]     # first sub-asset
some_list_asset[-1]    # last sub-asset
some_list_asset[1..3]  # 2nd, 3rd and 4th assets
some_list_asset[..3]   # 1st, 2nd, 3rd and 4th assets
some_list_asset[3..]   # 4th asset and everything after

Concat Operation sources

The concat operation does not take a source param (which would name one asset), it takes a sources array of asset names.

The named assets can be either singular assets or list assets.

concat flattens the list of assets and concatenates them all together.