composer - Documentation

An efficient middleware composer for Koa.

Source:

composer.js, line 2

Methods

(inner) compose(…input) → {function}

Source:

composer.js, line 32

Compose a method that will efficiently execute multiple middleware for Koa. This makes use of the reusify module to avoid allocating excess objects and functions during runtime when at all possible. As a result, memory churn should be reduced while V8 should be able to properly optimize these methods.

This can be used as a drop-in replacement for koa-compose.

FilterableMiddleware objects can be supplied, describing middleware that should be filtered to only run on specific paths.

Example

app.use(compose(cors(), cache(), router.middleware()));

Parameters:

Name	Type	Attributes	Description
`input`	function \| Array.<function()> \| composer~FilterableMiddleware \| Array.<FilterableMiddleware>	<repeatable>	The various middleware to compose together. This can consist of functions or arrays of functions. The input may also be comprised of objects that describe middleware that should be filtered to only run on specific paths.

Returns:

The composed middleware

Type: function

Type Definitions

FilterableMiddleware

Source:

composer.js, line 9

Properties:

Name	Type	Attributes	Default	Description
`fn`	function			Koa Middleware
`filtered`	Boolean	<optional>	`false`	Whether or not this middleware should actually be filtered.
`rich`	Boolean	<optional>	`false`	Whether the filter for this middleware is a function or a basic string for comparison.
`test`	String \| RegExp \| Object	<optional>		Required when `filtered` is true. Either a string for a `path.startsWith(...)` comparison or an object with a `test` method that accepts the current path. Conveniently, compiled regular expressions have just such a method.

Filterable Middleware

Type:

Object

Example

{
    fn: (ctx, next) => ctx.user ? next() : ctx.throw(401),
    filtered: true,
    rich: false,
    test: "/user"
}