refactor(javascript): group domain semantics and contracts (#907)

src/domain/javascript/javascriptSemanticMutationValues.ts

@@ -0,0 +1,65 @@
+import type { JavaScriptSemanticValue } from "./javascriptSemanticIr.js";
+
+/** Invalidate only slots that an explicit mutation can affect. */
+export const invalidateSemanticMutationPath = (
+  value: JavaScriptSemanticValue,
+  path: readonly (string | number | null)[],
+): JavaScriptSemanticValue => {
+  const [key, ...remaining] = path;
+  const unknown: JavaScriptSemanticValue = {
+    status: "unknown",
+    reason: "This property may have been mutated.",
+  };
+  if (key === undefined || key === null) return unknown;
+  if (value.status === "object") {
+    const name = String(key);
+    const observed = value.properties.some(
+      (property) => property.name === name,
+    );
+    const properties = value.properties.map((property) =>
+      property.name === name
+        ? {
+            ...property,
+            value: invalidateSemanticMutationPath(property.value, remaining),
+          }
+        : property,
+    );
+    return value.unknownProperties || !observed
+      ? {
+          status: "object",
+          properties,
+          unknownProperties: true,
+          omittedProperties: observed ? value.omittedProperties : null,
+        }
+      : {
+          status: "object",
+          properties,
+          unknownProperties: false,
+          omittedProperties: 0,
+        };
+  }
+  if (value.status === "array") {
+    const index = typeof key === "number" ? key : Number(key);
+    if (
+      !Number.isSafeInteger(index) ||
+      index < 0 ||
+      String(index) !== String(key)
+    )
+      return unknown;
+    const observed = value.items[index] !== undefined;
+    const items = value.items.map((item, position) =>
+      position === index
+        ? invalidateSemanticMutationPath(item, remaining)
+        : item,
+    );
+    return value.unknownItems || !observed
+      ? {
+          status: "array",
+          items,
+          unknownItems: true,
+          omittedItems: observed ? value.omittedItems : null,
+        }
+      : { status: "array", items, unknownItems: false, omittedItems: 0 };
+  }
+  return unknown;
+};