Hello ^^
There are some tables where values change over time, and when those changes occurred is significant. For example a todo list, or a kanban board. I know grist has a perfectly good backup and undo/history true, but as far as I could tell, this couldn’t be seen easily at a per-record level, and couldn’t easily be incorporated into, say a custom widget.
I built it using trigger formulas (on new and update records). This feels like a very hacky solution. It would be cool feature if you could turn on history tracking for a record natively in Grist. But for now, this might work 
If you know a better way to do this, please let me know!
The code and a readme are here: GitHub - kindrowboat/grist-change_log: a (probably cursed) way to have changelogs for records in grist
This is what the trigger formula currently looks like:
# ====================8<-----------------------------------
blacklist = ["change_log", "updated_at", "created_at"]
# ----------------------------->8==========================
import json
def jsonify_rec(changed_record):
def simplify(value):
if ISREF(value):
return value.id
elif ISREFLIST(value):
return ["L"] + [v.id for v in value]
elif isinstance(value, tuple):
return list(value)
return value
result = {k: simplify(v) for k, v in changed_record.items() if k not in blacklist}
return result
# Trigger formula code
current_snapshot = jsonify_rec(RECORD(rec, dates_as_iso=True))
logs_json = current_snapshot.get('change_log') or "[]"
logs = json.loads(logs_json)
previous_snapshot = logs[0]["snapshot"] if logs else {}
changed_fields = [
field for field in current_snapshot
if current_snapshot.get(field) != previous_snapshot.get(field)
]
log = {
"timestamp": NOW().isoformat(),
"changed": changed_fields,
"snapshot": current_snapshot
}
logs.insert(0, log) # Prepend the new log entry
return json.dumps(logs)
There’s also a custom widget you can install to view a concise change log for a given record.