Optimize Code Generation for Refinements

example/index.ts

@@ -12,10 +12,18 @@ const Byte = Type.Refine(UnsafeByte)
   .Check((value) => value < 256)
   .Done()
 
-console.log(Value.Check(Byte, 0)) // false
-console.log(Value.Check(Byte, 255)) // false
-console.log(Value.Check(Byte, -1)) // true
-console.log(Value.Check(Byte, NaN)) // true
+const A = Type.Object({
+  x: Byte,
+  y: Byte,
+  z: Byte,
+})
+
+console.log(Byte)
+console.log(TypeCompiler.Code(A))
+console.log(Value.Check(A, { x: 0, y: 0, z: 0 })) 
+console.log(Value.Check(Byte, 255)) 
+console.log(Value.Check(Byte, -1)) 
+console.log(Value.Check(Byte, NaN))
 
 // Todo: Error Tests
 // Todo: Investigate Error Propogation for Refinements

src/compiler/compiler.ts

@@ -457,10 +457,21 @@ export namespace TypeCompiler {
     yield `kind('${schema[Kind]}', ${instance}, ${value})`
   }
   function* FromRefine(schema: { [RefineKind]: Refinement[] }, references: TSchema[], value: string): IterableIterator<string> {
+    // Optimization: Refine functions may be called multiple times on the same type. This occurs
+    // if a type with refinements is embedded multiple times within the compiled type. Rather than
+    // generating duplicate entries in the refinement map, we can test if the refinement check
+    // function is already stored, if so, we return the instance key, otherwise create.
+    function ResolveRefinement(refinement: Refinement): number {
+      for (const [key, existing] of state.refinements) {
+        if (existing.check === refinement.check) return key
+      }
+      const key = state.refinements.size
+      state.refinements.set(key, refinement)
+      return key
+    }
     for (const refinement of schema[RefineKind]) {
-      const instance = state.refinements.size
-      state.refinements.set(instance, refinement)
-      yield `refine(${instance}, ${value})`
+      const key = ResolveRefinement(refinement)
+      yield `refine(${key}, ${value})`
     }
   }
   function* Visit(schema: TSchema, references: TSchema[], value: string, useHoisting: boolean = true): IterableIterator<string> {