1 files changed, 70 insertions, 0 deletions
diff --git a/packages/idb-bridge/src/util/valueToKey.ts b/packages/idb-bridge/src/util/valueToKey.ts
new file mode 100644
index 000000000..3a9e36786
--- /dev/null
+++ b/packages/idb-bridge/src/util/valueToKey.ts
@@ -0,0 +1,70 @@
+/*
+ Copyright 2017 Jeremy Scheff
+
+ 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 { DataError } from "./errors";
+import { Key } from "./types";
+
+// https://w3c.github.io/IndexedDB/#convert-a-value-to-a-input
+function valueToKey(input: any, seen?: Set<object>): Key | Key[] {
+    if (typeof input === "number") {
+        if (isNaN(input)) {
+            throw new DataError();
+        }
+        return input;
+    } else if (input instanceof Date) {
+        const ms = input.valueOf();
+        if (isNaN(ms)) {
+            throw new DataError();
+        }
+        return new Date(ms);
+    } else if (typeof input === "string") {
+        return input;
+    } else if (
+        input instanceof ArrayBuffer ||
+        (typeof ArrayBuffer !== "undefined" &&
+            ArrayBuffer.isView &&
+            ArrayBuffer.isView(input))
+    ) {
+        if (input instanceof ArrayBuffer) {
+            return new Uint8Array(input).buffer;
+        }
+        return new Uint8Array(input.buffer).buffer;
+    } else if (Array.isArray(input)) {
+        if (seen === undefined) {
+            seen = new Set();
+        } else if (seen.has(input)) {
+            throw new DataError();
+        }
+        seen.add(input);
+
+        const keys = [];
+        for (let i = 0; i < input.length; i++) {
+            const hop = input.hasOwnProperty(i);
+            if (!hop) {
+                throw new DataError();
+            }
+            const entry = input[i];
+            const key = valueToKey(entry, seen);
+            keys.push(key);
+        }
+        return keys;
+    } else {
+        throw new DataError();
+    }
+};
+
+export default valueToKey;