ParamsTokenFactory

Kind: Class

Source: packages/core/pipes/params-token-factory.ts

Part of: Core

ParamsTokenFactory normalizes route parameter metadata by converting known RouteParamtypes enum values into their string token equivalents. It is used by the pipes system to provide consistent parameter identifiers when resolving and applying pipes to controller arguments.

Methods

Diagram

mermaid
graph LR
  A[Route parameter metadata] --> B[ParamsTokenFactory]
  B --> C[exchangeEnumForString]
  C --> D[String parameter token]
  D --> E[Pipes context / parameter resolution]

Usage

ts
import { ParamsTokenFactory } from '@nestjs/core/pipes/params-token-factory';
import { RouteParamtypes } from '@nestjs/common/enums/route-paramtypes.enum';

const paramsTokenFactory = new ParamsTokenFactory();

const token = paramsTokenFactory.exchangeEnumForString(
  RouteParamtypes.BODY,
);

console.log(token); // "body"

AI Coding Instructions

• Use exchangeEnumForString() when pipe-related code needs a stable string token for a route parameter type.
• Preserve existing enum-to-string mappings when adding or modifying supported parameter types.
• Return unrecognized parameter values unchanged so custom or already-normalized tokens remain compatible.
• Keep this factory focused on token normalization; pipe execution and parameter extraction belong in their respective context creators.

Relationships

• IMPORTS → Paramtype
• IMPORTS → RouteParamtypes