[Bloblang] New Method must_array

[gramian]

Dear All,

I would like to propose a new method for bloblang. This method provisionally called must_array behaves as follows:

• if the underlying type is an array, must_array returns its input (identity)
• if the underlying type is not an array, must_array wraps its input in an array

Examples:

root = this.something.must_array()

# in: { "something": "Hi Benthos" }
# out: ["Hi Benthos"]

#in: { "something": [1,2,3,4] }
#out: [1,2,3,4]

Currently, one can emulate this behavior in bloblang:

root = if this.type() == "array" { this } else { [this] }

It could be discussed, how this function would behave for null: for example an empty array could be returned(?).

Why is this useful?

I am working with xml messages, which when parsed into json yield objects or strings if only one instance of a tag appears, and an array if multiple instances are found in one node. To process such results further with the same machinery these parsed tags need thave to be arrays, so map_each, fold, filter can be applied equally.

A real-life example for such an xml format is mods.

The emulated function can be made a map to be reused, but if I understand correctly, for example, it would need to be imported or redefined in every mapping of every branch in a workflow.

Thank you for considering my proposal!

PS: This came up in the "questions" Discord channel.

[mihaitodor]

Hey @gramian, I guess you could also use this.with("something").values().flatten() as a workaround.

[gramian]

This is also a good tip. Thank you.