docs: Update filter documentation

docs/docs/filters.md

@@ -11,53 +11,23 @@ In this case, we need to retrieve the body content from an Express.Request.
 So to do that, you must create a class and annotate it with the @@Filter@@
 decorator and in option, implement the @@IFilter@@ interface:
 
-```typescript
-import {Filter, IFilter, ParseService} from "@tsed/common";
+<<< @/docs/docs/snippets/filters/basic-filter.ts
 
-@Filter()
-export class BodyParamsFilter implements IFilter {
+Then create the decorator. This decorator will be used on a controller method.
 
-    constructor(private parseService: ParseService) {
-    }
+<<< @/docs/docs/snippets/filters/filter-decorator.ts
 
-    transform(expression: string, request, response) {
-        return this.parseService.eval(expression, request["body"]);
-    }
-}
-```
+And finally you can use your custom filter on your controller/middleware:
 
-Then create the decorator. This decorator will be used on a controller method.
+<<< @/docs/docs/snippets/filters/filter-usage.ts
+
+### UseFilter Options
+
+@@UseFilter@@ allow you to register your custom decorator with few options as following:
 
-```typescript
-import {Type} from "@tsed/core";
-import {BodyParamsFilter} from "../components/BodyParamsFilter";
-import {IParamOptions} from "../interfaces/IParamOptions";
-import {ParamTypes} from "../interfaces/ParamTypes";
-import {UseFilter} from "./useFilter";
-import {mapParamsOptions} from "./utils/mapParamsOptions";
-
-export function BodyParams(expression: string): ParameterDecorator;
-export function BodyParams(useType: Type<any> | Function): ParameterDecorator;
-export function BodyParams(options: IParamOptions<any>): ParameterDecorator;
-export function BodyParams(): ParameterDecorator;
-export function BodyParams(...args: any[]): ParameterDecorator {
-  const {expression, useType, useConverter = true, useValidation = true} = mapParamsOptions(args);
-
-  return UseFilter(BodyParamsFilter, {
-    expression,
-    useType,
-    useConverter,
-    useValidation,
-    paramType: ParamTypes.BODY
-  });
-}
-
-```
-
-::: tip
-To link the decorator with BodyParamsFilter, you must used the @@ParamRegistry@@ API.
-:::
-
-## Built-in filters
-
-<ApiList query="symbolName.endsWith('Filter') && symbolType === 'class'" />
+- `paramType` (ParamTypes): Parameter type like BODY, QUERY, PARAMS, etc...,
+- `required` (boolean, optional): Throw an error when if the value is undefined,
+- `expression` (string, optional): An expression to parse,
+- `useConverter` (boolean): Enable converterService to deserialize value,
+- `useValidation` (boolean): Enable ValidationService,
+- `useType` (boolean): Set explicitly the class/model used by the parameters.

docs/docs/snippets/filters/basic-filter.ts

@@ -0,0 +1,13 @@
+import {Filter, IFilter, ParseService} from "@tsed/common";
+import * as Express from "express";
+
+@Filter()
+export class CustomBodyParamFilter implements IFilter {
+
+  constructor(private parseService: ParseService) {
+  }
+
+  transform(expression: string, request: Express.Request, response: Express.Response) {
+    return this.parseService.eval(expression, request["body"]);
+  }
+}

docs/docs/snippets/filters/filter-decorator.ts

@@ -0,0 +1,14 @@
+import {IParamOptions, ParamTypes, UseFilter} from "@tsed/common";
+import {CustomBodyParamFilter} from "./CustomBodyParamFilter";
+
+export function CustomBodyParams(options: IParamOptions<any> = {}): ParameterDecorator {
+  const {expression, useType, useConverter = true, useValidation = true} = options;
+
+  return UseFilter(CustomBodyParamFilter, {
+    expression,
+    useType,
+    useConverter,
+    useValidation,
+    paramType: ParamTypes.BODY // for swagger
+  });
+}

docs/docs/snippets/filters/filter-usage.ts

@@ -0,0 +1,12 @@
+import {Controller, Post} from "../../../../packages/common/src/mvc/decorators";
+import {CustomBodyParams} from "./filter-decorator";
+
+
+@Controller("/")
+export class MyController {
+
+  @Post("/")
+  save(@CustomBodyParams({}) payload: any) {
+    console.log(payload);
+  }
+}