“undefined” creeping into append - how to debug?

Scripting
1

Hi - Completely new to JavaScript here

I’ve got a draft (code name Fragmence) with hundreds of lines structured like this:

Quote Blah blah blah #tag #tag2
Writing Prompt #tag2
What resources can they bring to bear? #question

My script is trying to pull a random line out. But I’m getting the word “undefined” in my append action at the bottom.

var fullFragDraft = Draft.find('51E1E4D4-F56E-415A-808F-C76E8091B71F')

var splitFrag = fullFragDraft.lines


// this is whete I'd like to filter lines based on words inside i.e. include lines with the text "#Modern" and exclude any lines witn the text "#question"

var filteredFrag = splitFrag
var numLines = filteredFrag.length
var RandLine = Math.round(Math.random() * numLines)
var ResultLine = splitFrag [RandLine]

draft.append ("\n\n" + RandLine + "\n" + filteredFrag.length + "\n" + ResultLine + "\n");

Output:

undefined

1529
2290
What resources can they bring to bear? #question

2

I’m getting the error even in the simplest case like

draft.append ("\nran\n");

Which outputs

 undefined
 ran

instead of just

 ran
3

I stopped using .append(string) and used

d.content = d.content + Randline

And the “undefined” is gone!

4

@_ry, I can see the same behaviour in both the append and the prepend Draft functions,

If I have this script.

draft.prepend("before:");
draft.append(":after");

Then run it against a draft with just three characters of content like this.

000

I would expect to get this output.

before:
000
:after

I get this output instead, with mysterious undefined entries.

before:undefined000undefined:after

@agiletortoise, can you reproduce this and confirm they are bugs?

5

Have you tried explicitly passing the separator argument? The docs say it is optional, but looks like the implementation might disagree. Docs

(will make note to test implementation as well)

6

Explicitly specifying the separator parameter works as I’d expect. The docs actually seem to reference the defaults as being new lines, which must be what is showing as undefined here.

7

That’s right - when I specify the second parameter in append it also works.

Docs say it’s optional but I guess it’s required.