Design Log 120 — `record(T)` Type in Jay-Action

Written for AI agents. See Log Methodology Note below for details.

Background

Jay-actions need to express Record<string, T> as output types. A real use case: VariantStockMap — variant IDs → option IDs → in-stock booleans (Record<string, Record<string, boolean>>). The existing type notation had no way to express typed record/map types. Empty objects {} produce Record<string, unknown>, but there was no notation for typed values.

Design

Add record(T) keyword to the compact type notation, following the enum(a | b | c) pattern. Supports nesting and all existing inner types via recursive parsing.

outputSchema:
  stock: record(boolean) # Record<string, boolean>
  variants: record(record(boolean)) # Record<string, Record<string, boolean>>
  labels: record(string) # Record<string, string>
  items: record(productCard) # Record<string, ProductCardViewState>

Implementation

Changes

compiler-shared/lib/jay-type.ts — Added record to JayTypeKind, JayRecordType class (mirrors JayArrayType), isRecordType() guard, equalJayTypes() case
compiler-shared/lib/jay-type-to-json-schema.ts — Added additionalProperties to JsonSchemaProperty, record → { type: 'object', additionalProperties: ... } conversion
compiler-jay-html/lib/action/action-parser.ts — record(...) detection in resolveStringType() with recursive inner type parsing
compiler-jay-html/lib/action/action-compiler.ts — renderType() renders Record<string, T>, collectImportedAliases() recurses into record items
Documentation — Added record(T) row to type notation tables in server-actions.md, plugins.md, contracts-and-plugins.md

Test Results

compiler-shared: 108/108 passing (including 2 new record JSON Schema tests)
compiler-jay-html actions: 35/35 passing (including 5 new parser + 4 new compiler tests)

Log Methodology Note

Note: These design logs are written primarily for AI agents as part of the Design Log methodology and made accessible here for human readers. The language and structure are optimized for machine consumption — expect precise, specification-style prose rather than narrative documentation.

Record Type In Jay-Action