idb wip

1 files changed, 108 insertions, 0 deletions

diff --git a/packages/idb-bridge/src/util/cmp.ts b/packages/idb-bridge/src/util/cmp.ts
new file mode 100644
index 000000000..9d0dc99a2
--- /dev/null
+++ b/packages/idb-bridge/src/util/cmp.ts
@@ -0,0 +1,108 @@
+/*
+ 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 valueToKey from "./valueToKey";
+
+const getType = (x: any) => {
+    if (typeof x === "number") {
+        return "Number";
+    }
+    if (x instanceof Date) {
+        return "Date";
+    }
+    if (Array.isArray(x)) {
+        return "Array";
+    }
+    if (typeof x === "string") {
+        return "String";
+    }
+    if (x instanceof ArrayBuffer) {
+        return "Binary";
+    }
+
+    throw new DataError();
+};
+
+// https://w3c.github.io/IndexedDB/#compare-two-keys
+const compareKeys = (first: any, second: any): -1 | 0 | 1 => {
+    if (second === undefined) {
+        throw new TypeError();
+    }
+
+    first = valueToKey(first);
+    second = valueToKey(second);
+
+    const t1 = getType(first);
+    const t2 = getType(second);
+
+    if (t1 !== t2) {
+        if (t1 === "Array") {
+            return 1;
+        }
+        if (
+            t1 === "Binary" &&
+            (t2 === "String" || t2 === "Date" || t2 === "Number")
+        ) {
+            return 1;
+        }
+        if (t1 === "String" && (t2 === "Date" || t2 === "Number")) {
+            return 1;
+        }
+        if (t1 === "Date" && t2 === "Number") {
+            return 1;
+        }
+        return -1;
+    }
+
+    if (t1 === "Binary") {
+        first = new Uint8Array(first);
+        second = new Uint8Array(second);
+    }
+
+    if (t1 === "Array" || t1 === "Binary") {
+        const length = Math.min(first.length, second.length);
+        for (let i = 0; i < length; i++) {
+            const result = compareKeys(first[i], second[i]);
+
+            if (result !== 0) {
+                return result;
+            }
+        }
+
+        if (first.length > second.length) {
+            return 1;
+        }
+        if (first.length < second.length) {
+            return -1;
+        }
+        return 0;
+    }
+
+    if (t1 === "Date") {
+        if (first.getTime() === second.getTime()) {
+            return 0;
+        }
+    } else {
+        if (first === second) {
+            return 0;
+        }
+    }
+
+    return first > second ? 1 : -1;
+};
+
+export default compareKeys;