What JSON Lines is
JSON Lines is one complete JSON object per line, with no enclosing array and no commas between records. The file is not valid JSON as a whole, and that is the point.
Log pipelines, machine learning datasets and anything that appends records or reads them in a stream.
What ActionScript is
An ActionScript Array of object literals.
Legacy Flash and AIR projects.
What changes when you convert JSON Lines to ActionScript
Each line is parsed on its own, so a corrupt record does not take the file with it. Keys are unioned across lines in first-seen order, so a record missing a field leaves that cell empty rather than shifting the columns.
Typed as Array, with double-quoted string values.
What carries over from JSON Lines to ActionScript
One property of the JSON Lines has no home in ActionScript, and it is worth knowing which before you convert.
JSON Lines can be read one record at a time. ActionScript has to be complete before it means anything, so the whole table is held in memory while it is written and a file that gets cut off part way through is not partly usable - it is unusable.
Both formats record types, so numbers, booleans and nulls survive as themselves rather than as text.
The identifier 007 comes out of the ActionScript as 007. Reading it as a number would have made it 7, and an id that changes value is worse than one that stays text.
The role "Analyst, data" survives with its comma, in one cell rather than split across two. That is the first thing to check in any converted table, and the usual place a ActionScript file goes wrong.
The quotes around Jonah "Jo" Pryce are escaped with a backslash in the ActionScript.