> Upsert (https://github.com/tc39/proposal-upsert): [Weak]Map.prototype.getOrInsert(), [Weak]Map.prototype.getOrInsertComputed()
Their usage of upsert appears different than I was used to:
Me: Upsert = Update or Insert
Them: Upsert = Get or Insert
Their usage of upsert appears different than I was used to:
Me: Upsert = Update or Insert
Them: Upsert = Get or Insert
I agree that their choice of labeling the proposal as "upsert" is less than ideal. However, this functionality is reminiscent of a very useful Perl capability known as autovivification[0] as described in the motivation section:
A common problem when using a Map or WeakMap is how to
handle doing an update when you're not sure if the key
already exists in the map.
If you use that operator and the value doesn't exist, it'll default create one and return a reference to that.
And as I'm writing this I realize why... references cannot be `null`.
`getOrInsert` here seems to be the Python "set_default" method on dicts, which is very useful at avoiding tedium in some basic data munging
Example:
update(store, (draft) => {
if (!draft.alertConfigurations.has(req.params.clusterId))
draft.alertConfigurations.set(req.params.clusterId, new Map());
const clusterAlerts = draft.alertConfigurations.get(req.params.clusterId);
req.body.forEach((alert) => clusterAlerts.set(alert.id, { ...alert, predefined: false }));
});It gives a caller the option of alternate logic based on the existence, or lack thereof, of a value.
> is that not just set?
No. The semantics of a "set" operation would overwrite an existing entry (if one exists).