2 files changed, 82 insertions, 0 deletions
diff --git a/packages/idb-bridge/src/util/canInjectKey.test.ts b/packages/idb-bridge/src/util/canInjectKey.test.ts
new file mode 100644
index 000000000..b57dd1c9a
--- /dev/null
+++ b/packages/idb-bridge/src/util/canInjectKey.test.ts
@@ -0,0 +1,24 @@
+/*
+ Copyright 2017 Jeremy Scheff
+ Copyright 20201 Taler Systems SA
+
+ Licensed under the Apache License, Version 2.0 (the "License");
+ you may not use this file except in compliance with the License.
+ You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
+ or implied. See the License for the specific language governing
+ permissions and limitations under the License.
+*/
+
+import test from "ava";
+import { canInjectKey } from "./canInjectKey";
+
+test("canInjectKey", (t) => {
+  t.false(canInjectKey("foo", null));
+  t.true(canInjectKey("foo", {}));
+});
diff --git a/packages/idb-bridge/src/util/canInjectKey.ts b/packages/idb-bridge/src/util/canInjectKey.ts
new file mode 100644
index 000000000..903a9d3de
--- /dev/null
+++ b/packages/idb-bridge/src/util/canInjectKey.ts
@@ -0,0 +1,58 @@
+/*
+ Copyright 2017 Jeremy Scheff
+ Copyright 20201 Taler Systems SA
+
+ Licensed under the Apache License, Version 2.0 (the "License");
+ you may not use this file except in compliance with the License.
+ You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
+ or implied. See the License for the specific language governing
+ permissions and limitations under the License.
+*/
+
+import { IDBKeyPath } from "../idbtypes";
+
+/**
+ * Check that a key could be injected into a value.
+ *
+ * https://www.w3.org/TR/IndexedDB/#check-that-a-key-could-be-injected-into-a-value
+ */
+export function canInjectKey(
+  keyPath: IDBKeyPath | IDBKeyPath[],
+  value: any,
+): boolean {
+  if (Array.isArray(keyPath)) {
+    throw new Error(
+      "The key paths used in this section are always strings and never sequences, since it is not possible to create a object store which has a key generator and also has a key path that is a sequence.",
+    );
+  }
+
+  const identifiers = keyPath.split(".");
+  if (identifiers.length === 0) {
+    throw new Error("Assert: identifiers is not empty");
+  }
+  identifiers.pop();
+
+  for (const identifier of identifiers) {
+    if (
+      value === null ||
+      (typeof value !== "object" && !Array.isArray(value))
+    ) {
+      return false;
+    }
+
+    const hop = value.hasOwnProperty(identifier);
+    if (!hop) {
+      return true;
+    }
+
+    value = value[identifier];
+  }
+
+  return value !== null && (typeof value === "object" || Array.isArray(value));
+}