README.md

middleware-io

middleware-io

Table of contents

References

• default

Classes

• Composer

Type Aliases

• BranchMiddlewareCondition
• BranchMiddlewareConditionFunction
• CaughtMiddlewareHandler
• LazyMiddlewareFactory
• Middleware
• MiddlewareReturn
• NextMiddleware
• NextMiddlewareReturn
• UnknownObject

Functions

• compose
• getAfterMiddleware
• getBeforeMiddleware
• getBranchMiddleware
• getCaughtMiddleware
• getConcurrencyMiddleware
• getEnforceMiddleware
• getFilterMiddleware
• getForkMiddleware
• getLazyMiddleware
• getOptionalMiddleware
• getTapMiddleware
• noopNext
• skipMiddleware
• stopMiddleware

References

default

Renames and re-exports compose

Type Aliases

BranchMiddlewareCondition

Ƭ BranchMiddlewareCondition<T>: BranchMiddlewareConditionFunction<T> | boolean

Possible types for branch condition

Type parameters

Name
T

Defined in

types.ts:34

---

BranchMiddlewareConditionFunction

Ƭ BranchMiddlewareConditionFunction<T>: (context: T) => Promise<boolean> | boolean

Asynchronous function for branch condition

Type parameters

Name
T

Type declaration

▸ (context): Promise<boolean> | boolean

Parameters

Name	Type
context	T

Returns

Promise<boolean> | boolean

Defined in

types.ts:29

---

CaughtMiddlewareHandler

Ƭ CaughtMiddlewareHandler<T>: (context: T, error: Error) => MiddlewareReturn

Handler for catching errors in middleware chains

Type parameters

Name
T

Type declaration

▸ (context, error): MiddlewareReturn

Parameters

Name	Type
context	T
error	Error

Returns

MiddlewareReturn

Defined in

types.ts:44

---

LazyMiddlewareFactory

Ƭ LazyMiddlewareFactory<T>: (context: T) => Promise<Middleware<T>> | Middleware<T>

Asynchronous factory to create middleware

Type parameters

Name
T

Type declaration

▸ (context): Promise<Middleware<T>> | Middleware<T>

Parameters

Name	Type
context	T

Returns

Promise<Middleware<T>> | Middleware<T>

Defined in

types.ts:39

---

Middleware

Ƭ Middleware<T>: (context: T, next: NextMiddleware) => MiddlewareReturn

Basic middleware

Type parameters

Name
T

Type declaration

▸ (context, next): MiddlewareReturn

Parameters

Name	Type
context	T
next	NextMiddleware

Returns

MiddlewareReturn

Defined in

types.ts:24

---

MiddlewareReturn

Ƭ MiddlewareReturn: unknown

Returns the type of response middleware

Defined in

types.ts:14

---

NextMiddleware

Ƭ NextMiddleware: () => Promise<NextMiddlewareReturn>

Call the next middleware from the chain

Type declaration

▸ (): Promise<NextMiddlewareReturn>

Returns

Promise<NextMiddlewareReturn>

Defined in

types.ts:9

---

NextMiddlewareReturn

Ƭ NextMiddlewareReturn: unknown

Returns the type of response middleware

Defined in

types.ts:4

---

UnknownObject

Ƭ UnknownObject: Record<string, unknown>

Instead of object

Defined in

types.ts:19

Functions

compose

▸ compose<T>(middlewares): Middleware<T>

Compose an array of middleware handlers into a single handler

Type parameters

Name
T

Parameters

Name	Type	Description
middlewares	Middleware<T>[]	The array of middleware

Returns

Middleware<T>

Composed middleware

Defined in

compose.ts:12

---

getAfterMiddleware

▸ getAfterMiddleware<T>(middleware, afterMiddleware): Middleware<T>

Runs the second middleware after the main

Example:

getAfterMiddleware(
  sendSecureData,
  clearSecurityData
);

Type parameters

Name
T

Parameters

Name	Type
middleware	Middleware<T>
afterMiddleware	Middleware<T>

Returns

Middleware<T>

Defined in

snippets.ts:192

---

getBeforeMiddleware

▸ getBeforeMiddleware<T>(beforeMiddleware, middleware): Middleware<T>

Runs the second middleware before the main

Example:

getBeforeMiddleware(
  myMockMiddleware,
  ouputUserData
);

Type parameters

Name
T

Parameters

Name	Type
beforeMiddleware	Middleware<T>
middleware	Middleware<T>

Returns

Middleware<T>

Defined in

snippets.ts:170

---

getBranchMiddleware

▸ getBranchMiddleware<T>(condition, trueMiddleware, falseMiddleware): Middleware<T>

By condition splits the middleware

Example:

getBranchMiddleware(
  async context => context.is('Content-Type', 'json'),
  myBodyParser.json(),
  myBodyParser.urlencoded()
);

Static condition

getBranchMiddleware(
  process.env.NODE_ENV === 'production',
  logger.loggedContextToFile(),
  logger.loggedContextToConsole()
);

Type parameters

Name
T

Parameters

Name	Type
condition	BranchMiddlewareCondition<T>
trueMiddleware	Middleware<T>
falseMiddleware	Middleware<T>

Returns

Middleware<T>

Defined in

snippets.ts:109

---

getCaughtMiddleware

▸ getCaughtMiddleware<T>(errorHandler): Middleware<T>

Catches errors in the middleware chain

Example:

getCaughtMiddleware((context, error) => {
  if (error instanceof NetworkError) {
    return context.send('Sorry, network issues 😔');
  }

  throw error;
})

Without a snippet, it would look like this:

async (context, next) => {
  try {
    await next();
  } catch (error) {
    if (error instanceof NetworkError) {
      return context.send('Sorry, network issues 😔');
    }

    throw error;
  }
};

Type parameters

Name
T

Parameters

Name	Type
errorHandler	CaughtMiddlewareHandler<T>

Returns

Middleware<T>

Defined in

snippets.ts:262

---

getConcurrencyMiddleware

▸ getConcurrencyMiddleware<T>(middlewares): Middleware<T>

Concurrently launches middleware, the chain will continue if next() is called in all middlewares

Warning: Error interrupts all others

Example:

getConcurrencyMiddleware(
  initializeUser,
  initializeSession,
  initializeDatabase
);

Type parameters

Name
T

Parameters

Name	Type
middlewares	Middleware<T>[]

Returns

Middleware<T>

Defined in

snippets.ts:288

---

getEnforceMiddleware

▸ getEnforceMiddleware<T>(beforeMiddleware, middleware, afterMiddleware): Middleware<T>

Runs middleware before and after the main

Example:

getEnforceMiddleware(
  prepareData,
  sendData,
  clearData
);

#### Type parameters

| Name |
| :------ |
| `T` |

#### Parameters

| Name | Type |
| :------ | :------ |
| `beforeMiddleware` | [`Middleware`](README.md#middleware)\<`T`\> |
| `middleware` | [`Middleware`](README.md#middleware)\<`T`\> |
| `afterMiddleware` | [`Middleware`](README.md#middleware)\<`T`\> |

#### Returns

[`Middleware`](README.md#middleware)\<`T`\>

#### Defined in

[snippets.ts:214](https://github.com/negezor/middleware-io/blob/cfc102d315382709d9f9d43771812ee5ab488e62/src/snippets.ts#L214)

___

### getFilterMiddleware

▸ **getFilterMiddleware**\<`T`\>(`condition`, `filterMiddleware`): [`Middleware`](README.md#middleware)\<`T`\>

Conditionally runs middleware or stops the chain

Example:

```ts
getFilterMiddleware(
  context => context.authorized,
  middlewareForAuthorized
);

Type parameters

Name
T

Parameters

Name	Type
condition	BranchMiddlewareCondition<T>
filterMiddleware	Middleware<T>

Returns

Middleware<T>

Defined in

snippets.ts:152

---

getForkMiddleware

▸ getForkMiddleware<T>(middleware): Middleware<T>

Runs the middleware at the next event loop and force call next()

Example:

getForkMiddleware((context) => {
  statisticsMiddlewares(context).catch(console.error);
});

Type parameters

Name
T

Parameters

Name	Type
middleware	Middleware<T>

Returns

Middleware<T>

Defined in

snippets.ts:79

---

getLazyMiddleware

▸ getLazyMiddleware<T>(factory): Middleware<T>

Lazily asynchronously gets middleware

Example:

getLazyMiddleware(async (context) => {
  const route = await getSomeRoute(context.path) // Promise<Function>;

  return route;
});

Type parameters

Name
T

Parameters

Name	Type
factory	LazyMiddlewareFactory<T>

Returns

Middleware<T>

Defined in

snippets.ts:36

---

getOptionalMiddleware

▸ getOptionalMiddleware<T>(condition, optionalMiddleware): Middleware<T>

Conditionally runs optional middleware or skips middleware

Example:

getOptionalMiddleware(
  context => context.user.isAdmin,
  addFieldsForAdmin
);

Type parameters

Name
T

Parameters

Name	Type
condition	BranchMiddlewareCondition<T>
optionalMiddleware	Middleware<T>

Returns

Middleware<T>

Defined in

snippets.ts:135

---

getTapMiddleware

▸ getTapMiddleware<T>(middleware): Middleware<T>

Runs the middleware and force call next()

Example:

getTapMiddleware((context) => {
  console.log('Context', context);
});

Type parameters

Name
T

Parameters

Name	Type
middleware	Middleware<T>

Returns

Middleware<T>

Defined in

snippets.ts:60

---

noopNext

▸ noopNext(): Promise<unknown>

Noop for call next() in middleware

Returns

Promise<unknown>

Defined in

helpers.ts:30

---

skipMiddleware

▸ skipMiddleware<T>(context, next): Promise<unknown>

Call next() in middleware

Type parameters

Name
T

Parameters

Name	Type
context	T
next	NextMiddleware

Returns

Promise<unknown>

Defined in

snippets.ts:16

---

stopMiddleware

▸ stopMiddleware<T>(context, next): Promise<void>

Does not call next() in middleware

Type parameters

Name
T

Parameters

Name	Type
context	T
next	NextMiddleware

Returns

Promise<void>

Defined in

snippets.ts:21