Max P.
8235680904
- Consolidates `Handler` and `Middleware` types under `Types` module - Replaces `IHandler` and `IMiddleware` interfaces with typed functions - Simplifies imports and improves code organization - Enhances debugging with named handlers and middlewares
52 lines
1.9 KiB
TypeScript
52 lines
1.9 KiB
TypeScript
import { IContext } from '../Interfaces/IContext.ts';
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/**
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* Represents a middleware function in the HTTP request pipeline.
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*
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* Middleware is a core mechanism to intercept, observe, or modify the request lifecycle.
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* It can be used for tasks such as logging, authentication, input validation,
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* metrics collection, or response transformation.
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*
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* Each middleware receives a fully-typed request context and a `next()` function
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* to invoke the next stage of the pipeline. Middleware may choose to short-circuit
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* the pipeline by returning a `Response` early.
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*
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* @template TContext The specific context type for this middleware, including state, params, and query information.
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*/
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type Middleware<TContext extends IContext = IContext> = (
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ctx: TContext,
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next: () => Promise<Response>,
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) => Promise<Response>;
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/**
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* Represents a middleware function with an associated name.
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*
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* This is useful for debugging, logging, or when you need to reference
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* the middleware by name in your application.
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*
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* @template TContext The specific context type for this middleware, including state, params, and query information.
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*/
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type NamedMiddleware<TContext extends IContext = IContext> =
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& Middleware<TContext>
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& { name?: string };
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export type { NamedMiddleware as Middleware };
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/**
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* Type guard to verify whether a given value is a valid `IMiddleware` function.
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*
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* This guard checks whether the input is a function that accepts exactly two arguments.
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* Note: This is a structural check and cannot fully guarantee the semantics of a middleware.
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*
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* @param value - The value to test.
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* @returns `true` if the value is structurally a valid middleware function.
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*/
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export function isMiddleware<TContext extends IContext = IContext>(
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value: unknown,
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): value is Middleware<TContext> {
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return (
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typeof value === 'function' &&
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value.length === 2 // ctx, next
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);
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}
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