use-middleware

Allows middleware to be added to any function call.

Example

Api

use

Use-middleware exposed one api :

use(argsObject: { [key: string]: any }, middlewareArray: MiddlewareFunc[], handlerFunc: HandlerFunc): Promise

Use will call each middleware in order, passing it the args and finally resolve the promise with the return value from the handler func. To handle errors in middlware you can pass the error to the next function and the promise will reject with the error.

Params

argsObject: { [key: string]: any }

The arguments object will be passed to each middleware and finally the handler.

middlewareArray: MiddlewareFunc[]

An array of middleware functions which will be called in order before the handler.

handlerFunc: HandlerFunc

The handler function will be called after the middleware functions.

Types

MiddlewareFunc = (argsObject, next: NextFunc, previous) => void

Middleware functions will be called with three paramaters. The argsObject, the next function in the pipeline and the value with which the previous function was called.

Middleware functions can do their work and then add properties to the argsObject. Once complete call the next function with any data to pass which will be received as the previous param.

HandlerFunc = (argsObject, previous: any) => any

The handler function will be called at the end of the middleware chain with the argsObject and and values passed to next from the last middleware.

nextFunc = (err: Error | string, data: any) => void

The next function is passed to each middleware and called there to move control to the next middleware. It takes two arguments, the first is any errors from the middleware, the second any data you would like to pass to the following function.