Metabase immutable wrapper classes

immutable-wrappers.md

metabase-lib/lib/metadata:

• "Base" base class
• copies properties
• also includes "_plainObject"
• external logic sets up references, lame: "metabase/selectors/metadata"

metabase-lib/lib/Dimension.js:

• "Dimension" base class, encode each clause as a different subclass
• also includes optional "_parent" (actually a child in the tree, i.e. ["field-id", 1] is a _parent in ["datetime-field", ["field-id", 1], "month"]) and "_args" which are rest of clause args (month the datetime-field or 1 in the field-id)
• also includes "_metadata" and "_query" properties
• has basic parseMBQL functionality

metabase-lib/lib/queries/structured: "MBQLArrayClause" and "MBQLObjectClause" base classes inherit from Array and Object

• also includes "_index" and "_query" private properties
• can be treated as original objects or wrappers, JSON.stringify(wrapper) works
• support immutable updates

tlrobinson/vanilla

• https://github.com/tlrobinson/vanilla/blob/master/src/vanilla.test.ts
• "VanillaArray" and "VanillaObject" base classes inherit from Array and Object
• also includes "_parser", "_parent", "_key", "_meta" private properties
• can be treated as original objects or wrappers, JSON.stringify(wrapper) works
• has advanced parse functionality
• support immutable updates
• TypeScript support

tlrobinson/vanilla/mbql:

• https://github.com/tlrobinson/vanilla/blob/master/src/mbql.test.ts
• "MBQLArray", "MBQLTuple", and "MBQLObject" base classes inherit from "VanillaArray" and "VanillaObject"
• also includes "parent", "metadata", "query", and "question" methods