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observablehq / stdlib

The Observable standard library.
https://observablehq.com/@observablehq/standard-library
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Handle column renaming in makeQueryTemplate and __table #345

Closed annie closed 1 year ago

annie commented 1 year ago

Implement column renaming in stdlib. Specifically, we now set column name overrides based on the names property in node.data.operations, which is added in this PR.

For SQL data sources, we do this by modifying the SELECT clause. For in-memory data sources, we create a copy of the source data and modify it to use the new names.

annie commented 1 year ago

hm looks like CI is failing because String.replaceAll (which i added in the unit test) isn't available in Node 14. i'll update it to just use .replace.

annie commented 1 year ago

oh interesting! in my first pass i had added names to select as a new property, but that ended up feeling unwieldy – your suggestion seems cleaner though. i'll take a shot at updating it in the monorepo PR and see if i run into any issues.

annie commented 1 year ago

@mbostock i ran into one major issue while trying to implement your suggestion, which is that it doesn't allow us to preserve the renamed name when a user hides the column. we could potentially get around this by adding a hidden flag to each columns object and toggling that when we hide a column, instead of removing the object from the array, but that would require a fairly significant set of changes and i'm not sure it's worth doing.

given that, i think i'd prefer to stick with this operations.names approach, unless you have strong objections and/or other ideas!

mbostock commented 1 year ago

@annie does that mean we’re still selecting and returning columns that are hidden when the query is run?

annie commented 1 year ago

no we don't actually select hidden columns, we just keep the name information for that column in operations.names. that allows us to still show the renamed name in the columns dropdown (where hidden columns are listed in a deselected state), and the column will preserve its renamed name if it's reselected.

mbostock commented 1 year ago

@annie Got it. Sorry, still waking up! ☕ 👍

mbostock commented 1 year ago

No further suggestions from me. I’ll leave the reviewing to @libbey-observable and @mkfreeman! Thanks y’all. 🙏