Rename files

ts/types/IndexedDB.std.ts

@@ -0,0 +1,22 @@
+// Copyright 2018 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+// IndexedDB doesn’t support boolean indexes so we map `true` to 1 and `false`
+// to `0`, i.e. `IndexableBoolean`.
+// N.B. Using `undefined` allows excluding an entry from an index. Useful
+// when index size is a consideration or one only needs to query for `true`,
+// i.e. `IndexablePresence`.
+export type IndexableBoolean = IndexableFalse | IndexableTrue;
+export type IndexablePresence = undefined | IndexableTrue;
+
+type IndexableFalse = 0;
+type IndexableTrue = 1;
+
+export const INDEXABLE_FALSE: IndexableFalse = 0;
+export const INDEXABLE_TRUE: IndexableTrue = 1;
+
+export const toIndexableBoolean = (value: boolean): IndexableBoolean =>
+  value ? INDEXABLE_TRUE : INDEXABLE_FALSE;
+
+export const toIndexablePresence = (value: boolean): IndexablePresence =>
+  value ? INDEXABLE_TRUE : undefined;