# Middleware

```ts
interface Middleware<TArgs extends unknown[], TReturn>
```

A general function that can be used to surround any other function
or value.

### Examples
#### Example 1
```ts
import type { Operation } from "effection";

function* DbMiddleware(args, next): <[string], Operation<{ id: number; title: string }[]>> {
  let [sql] = args;
  let start = Date.now();
  try {
    return yield* next(...args);
  } finally {
    console.log("query ms", Date.now() - start, sql);
  }
};
```

---


### Type Parameters
TArgs extends unknown&lbrack;&rbrack;


TReturn

[View code](https://github.com/thefrontside/effection/tree/effection-v4.2.0/lib/types.ts#L486)