From 69bdfc5daa01a96dbcc9dbc91333a38b95b0ae1b Mon Sep 17 00:00:00 2001
From: Thiago de Arruda <tpadilha84@gmail.com>
Date: Mon, 21 Nov 2016 20:13:00 -0300
Subject: [PATCH] levelup: Add declarations for custom encodings.

Levelup `keyEncoding`/`valueEncoding` options also accept an object that
implements a custom encoding, add declarations to enable it.
---
 levelup/index.d.ts       | 30 +++++++++++++++++++++---------
 levelup/levelup-tests.ts | 28 ++++++++++++++++++++++++++--
 2 files changed, 47 insertions(+), 11 deletions(-)

diff --git a/levelup/index.d.ts b/levelup/index.d.ts
index dd30c96ca9..c547291e45 100644
--- a/levelup/index.d.ts
+++ b/levelup/index.d.ts
@@ -1,14 +1,26 @@
 // Type definitions for LevelUp 
-// Project: https://github.com/rvagg/node-levelup
+// Project: https://github.com/Level/levelup
 // Definitions by: Bret Little <https://github.com/blittle>
+// Definitions by: Thiago de Arruda <https://github.com/tarruda>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
 
+/// <reference types="node" />
+
+interface CustomEncoding {
+    encode(val: any): Buffer| string;
+    decode(val: Buffer | string): any;
+    buffer: boolean;
+    type: string;
+}
+
+type Encoding = string | CustomEncoding;
+
 interface Batch {
     type: string;
     key: any;
     value?: any;
-    keyEncoding?: string;
-    valueEncoding?: string;
+    keyEncoding?: Encoding;
+    valueEncoding?: Encoding;
 }
 interface LevelUp {
     open(callback ?: (error : any) => any): void;
@@ -17,12 +29,12 @@ interface LevelUp {
     put(key: any, value: any, options?: { sync?: boolean }, callback ?: (error: any) => any): void;
     get(key: any, callback ?: (error: any, value: any) => any): void;
 
-    get(key: any, options ?: { keyEncoding?: string; fillCache?: boolean }, callback ?: (error: any, value: any) => any): void;
+    get(key: any, options ?: { keyEncoding?: Encoding; fillCache?: boolean }, callback ?: (error: any, value: any) => any): void;
     del(key: any, callback ?: (error: any) => any): void;
-    del(key: any, options ?: { keyEncoding?: string; sync?: boolean }, callback ?: (error: any) => any): void;
+    del(key: any, options ?: { keyEncoding?: Encoding; sync?: boolean }, callback ?: (error: any) => any): void;
 
 
-    batch(array: Batch[], options?: { keyEncoding?: string; valueEncoding?: string; sync?: boolean }, callback?: (error?: any)=>any): void;
+    batch(array: Batch[], options?: { keyEncoding?: Encoding; valueEncoding?: Encoding; sync?: boolean }, callback?: (error?: any)=>any): void;
     batch(array: Batch[], callback?: (error?: any)=>any): void;
     batch():LevelUpChain;
     isOpen():boolean;
@@ -39,7 +51,7 @@ interface LevelUpChain {
     put(key: any, value: any): LevelUpChain;
     put(key: any, value: any, options?: { sync?: boolean }): LevelUpChain;
     del(key: any): LevelUpChain;
-    del(key: any, options ?: { keyEncoding?: string; sync?: boolean }): LevelUpChain;
+    del(key: any, options ?: { keyEncoding?: Encoding; sync?: boolean }): LevelUpChain;
     clear(): LevelUpChain;
     write(callback?: (error?: any)=>any) : LevelUpChain;
 }
@@ -49,8 +61,8 @@ interface levelupOptions {
     errorIfExists?: boolean; 
     compression?: boolean; 
     cacheSize?: number; 
-    keyEncoding?: string; 
-    valueEncoding?: string; 
+    keyEncoding?: Encoding; 
+    valueEncoding?: Encoding; 
     db?: string
 }
 
diff --git a/levelup/levelup-tests.ts b/levelup/levelup-tests.ts
index 4349c2864c..57eea64e63 100644
--- a/levelup/levelup-tests.ts
+++ b/levelup/levelup-tests.ts
@@ -1,7 +1,31 @@
-
-
 import levelup = require("levelup");
 
+interface BufferEncoding {
+    encode(val: any): Buffer;
+    decode(val: Buffer): any;
+    buffer: boolean;
+    type: string;
+}
+
+interface StringEncoding {
+    encode(val: any): string;
+    decode(val: string): any;
+    buffer: boolean;
+    type: string;
+}
+
+declare const bufferEncoding: BufferEncoding;
+declare const stringEncoding: StringEncoding;
+
+var db1 = levelup("db1", {
+    keyEncoding: bufferEncoding,
+    valueEncoding: bufferEncoding
+});
+var db2 = levelup("db2", {
+    keyEncoding: stringEncoding,
+    valueEncoding: stringEncoding
+});
+
 var db = levelup('./mydb')
 db.open();
 db.close();