feat: add nonEmptyRecord refiner (#3288)

This PR adds a new struct refiner to validate that a record is not
empty.

Author: GuillaumeRx

packages/examples/packages/browserify-plugin/snap.manifest.json

@@ -7,7 +7,7 @@
     "url": "https://github.com/MetaMask/snaps.git"
   },
   "source": {
-    "shasum": "2WLcpc3RXg2Up0zeSMxWS/2rsVI1bC1iHCHAhzc3DOA=",
+    "shasum": "2XIZ9NDtR8XhO4hsAxS89GtjVkpwj/iTuHUv2P0TKYk=",
     "location": {
       "npm": {
         "filePath": "dist/bundle.js",

packages/examples/packages/browserify/snap.manifest.json

@@ -7,7 +7,7 @@
     "url": "https://github.com/MetaMask/snaps.git"
   },
   "source": {
-    "shasum": "LQYiFCEu2fQXCuzfYHVpFfqffCbzzUjaqH7kPwgBfNc=",
+    "shasum": "4U6ZsKhhX3XQp20W7rLNWpaExEasUgcSU/+Q/UQQNns=",
     "location": {
       "npm": {
         "filePath": "dist/bundle.js",

packages/snaps-sdk/src/index.ts

@@ -11,6 +11,7 @@ export {
   enumValue,
   typedUnion,
   selectiveUnion,
+  nonEmptyRecord,
 } from './internals';
 
 // Re-exported from `@metamask/utils` for convenience.

packages/snaps-sdk/src/internals/structs.test.ts

@@ -5,9 +5,16 @@ import {
   object,
   string,
   validate,
+  any,
 } from '@metamask/superstruct';
 
-import { enumValue, literal, typedUnion, union } from './structs';
+import {
+  enumValue,
+  literal,
+  typedUnion,
+  union,
+  nonEmptyRecord,
+} from './structs';
 import type { BoxElement } from '../jsx';
 import { Footer, Icon, Text, Button, Box } from '../jsx';
 import {
@@ -145,3 +152,27 @@ describe('typedUnion', () => {
     ]);
   });
 });
+
+describe('nonEmptyRecord', () => {
+  it.each([
+    { foo: 'bar' },
+    {
+      a: {
+        b: 'c',
+      },
+    },
+  ])('validates "%p"', (value) => {
+    const struct = nonEmptyRecord(string(), any());
+
+    expect(is(value, struct)).toBe(true);
+  });
+
+  it.each(['foo', 42, null, undefined, [], {}, [1, 2, 3]])(
+    'does not validate "%p"',
+    (value) => {
+      const struct = nonEmptyRecord(string(), any());
+
+      expect(is(value, struct)).toBe(false);
+    },
+  );
+});

packages/snaps-sdk/src/internals/structs.ts

@@ -2,6 +2,8 @@ import type { AnyStruct, Infer, InferStructTuple } from '@metamask/superstruct';
 import {
   Struct,
   define,
+  record,
+  refine,
   literal as superstructLiteral,
   union as superstructUnion,
 } from '@metamask/superstruct';
@@ -217,3 +219,19 @@ export function selectiveUnion<Selector extends (value: any) => AnyStruct>(
     },
   });
 }
+
+/**
+ * Refine a struct to be a non-empty record and disallows usage of arrays.
+ *
+ * @param Key - The struct for the record key.
+ * @param Value - The struct for the record value.
+ * @returns The refined struct.
+ */
+export function nonEmptyRecord<Key extends string, Value>(
+  Key: Struct<Key>,
+  Value: Struct<Value>,
+) {
+  return refine(record(Key, Value), 'Non-empty record', (value) => {
+    return !Array.isArray(value) && Object.keys(value).length > 0;
+  });
+}