fix: add sanity checks to type immutablity override settings

Author: RebeccaStevens

src/settings/immutability.ts

@@ -71,19 +71,47 @@ function loadImmutabilityOverrides(
     ? overridesSetting
     : overridesSetting.values ?? [];
 
-  const upgraded = raw.map(
-    ({ type, to, from }) =>
-      ({
-        type,
-        to: typeof to === "string" ? Immutability[to] : to,
-        from:
-          from === undefined
-            ? undefined
-            : typeof from === "string"
-            ? Immutability[from]
-            : from,
-      }) as ImmutabilityOverrides[number],
-  );
+  const upgraded = raw.map((rawValue) => {
+    const { type, to, from, ...rest } = rawValue;
+    const value = {
+      type,
+      to: typeof to === "string" ? Immutability[to] : to,
+      from:
+        from === undefined
+          ? undefined
+          : typeof from === "string"
+          ? Immutability[from]
+          : from,
+    } as ImmutabilityOverrides[number];
+
+    if (value.type === undefined) {
+      // eslint-disable-next-line functional/no-throw-statements
+      throw new Error(
+        `Override is missing required "type" property. Value: "${JSON.stringify(
+          rawValue,
+        )}"`,
+      );
+    }
+    if (value.to === undefined) {
+      // eslint-disable-next-line functional/no-throw-statements
+      throw new Error(
+        `Override is missing required "to" property. Value: "${JSON.stringify(
+          rawValue,
+        )}"`,
+      );
+    }
+    const restKeys = Object.keys(rest);
+    if (restKeys.length > 0) {
+      // eslint-disable-next-line functional/no-throw-statements
+      throw new Error(
+        `Override is contains unknown property(s) "${restKeys.join(
+          ", ",
+        )}". Value: "${JSON.stringify(rawValue)}"`,
+      );
+    }
+
+    return value;
+  });
 
   const keepDefault =
     Array.isArray(overridesSetting) || overridesSetting.keepDefault !== false;