Update README.MD

Author: divanc

README.MD

@@ -1,3 +1,96 @@
-# @lfg/query-coder
+## @lfg/query-coder
+URL query coder/decoder with configurable user pattern. It provides the most comfortable experience for encoding and decoding complex nested filter objects. [Check out example for more info](#example).
 
-#### URL query coder/decoder
+
+### Installation
+```zsh
+yarn add @lfg/query-coder
+```
+
+### Basic Example
+Imaging having a such interface for your querying filters:
+```ts
+type SearchGroupsFilter = {
+  gameId?: 'WorldOfWarcraft' | 'WildRift' | 'LostArk';
+  gameMode?: GameMode;
+  from?: Date;
+  language?: Language;
+  
+  lostArk?: LostArkFilterInput;
+  wildRift?: WildRiftFilterInput;
+  wow?: WowFilterInput;
+};
+```
+
+Let's take 1 example of this:
+```ts
+const filters: SearchGroupsFilter = {
+  gameId: "WorldOfWarcraft",
+  gameMode: GameMode.WowMythicPlus,
+  language: Language.En,
+  wow: {
+    faction: WowFaction.Alliance,
+    dungeon: WowDungeon.MistsOfTirnaScithe,
+    minRioRating: 1400,
+    region: WowRegion.Europe,
+  },
+};
+
+```
+Which should result in `const query = "game=wow&mode=mplus&language=en&faction=alliance&dungeon=mots&rating=1400&region=eu"`. 
+So we want to: 
+* flatten nested filter object in a query string  
+* rename certain keys (`gameMode` -> `mode`)
+* re-map certain values (`WorldOfWarcraft` -> `wow`)
+
+With this lib, you can init `QueryCoder` and that's it! 🎉
+```ts
+import { QueryCoder, QueryHandler } from '@lfg/query-coder';
+
+// passing generic interface checks, whether node keys
+// are the same as in provided interface
+const query = new QueryCoder<SearchGroupsFilter>({
+  gameId: new QueryHandler({ 
+    query: "game",
+    aliases: {
+      WorldOfWarcraft: "wow",
+      WildRift: "wr",
+      LostArk: "la",
+    },
+  }),
+  gameMode: new QueryHandler({ query: "mode" }),
+  language: new QueryHandler({ query: "language" }),
+  wow: {
+    faction: new QueryHandler({ 
+      query: "faction",
+      /**
+       * decodeCondition is Partial of generic
+       * if decodeCondition is set, search query would be handled
+       * with this handler only if decodeCondition matches query
+       * For more info, check out section below
+       */
+      decodeCondition: { gameId: "WorldOfWarcraft" },
+    }),
+    dungeon: new QueryHandler({
+      query: "dungeon",
+      decodeCondition: { gameId: "WorldOfWarcraft" },
+    }),
+    minRioRating: new QueryHandler({
+      query: "minRioRating",
+      decodeCondition: { gameId: "WorldOfWarcraft" },
+      /**
+       * You should provide a primitive type, which is different from string
+       * Otherwise, url query "foo=313" can result in an unexpected result
+       */
+      type: Type.Number,
+    }),
+    region: new QueryHandler({
+      query: "region",
+      decodeCondition: { gameId: "WorldOfWarcraft" },
+    }),
+  },
+});
+
+query.encode(filters); // should result in query variable
+query.decode(query); // should result in filters variable
+```