middleware-must-call-next - ESLint plugin rules

This rule requires middleware functions registered via defineMiddlewares to reference their next parameter.

Severity#

warn. This rule is enabled in the recommended preset.

What it Targets#

This rule targets the src/api/middlewares.ts file. It reports a middleware function that declares a next parameter but never references it, which stops the middleware chain.

The following code is reported by the rule:

src/api/middlewares.ts
1export default defineMiddlewares({2  routes: [3    {4      matcher: "/store/custom",5      middlewares: [(req, res, next) => { res.json({}) }],6    },7  ],8})

Instead, call next so the chain continues:

src/api/middlewares.ts
1export default defineMiddlewares({2  routes: [3    {4      matcher: "/store/custom",5      middlewares: [(req, res, next) => { next() }],6    },7  ],8})

Why it's Important#

A middleware that doesn't call next (or end the response) leaves the request hanging, so the route handler is never reached. Referencing next keeps the middleware chain moving.

Learn more in the Middlewares documentation.

Fixable#

This rule isn't auto-fixable.

Turn it Off#

To turn off this rule, set it to off in your ESLint configuration:

eslint.config.ts
1import { defineConfig } from "eslint/config"2import medusa from "@medusajs/eslint-plugin"3
4export default defineConfig([5  ...medusa.configs.recommended,6  {7    rules: {8      "@medusajs/middleware-must-call-next": "off",9    },10  },11])

Or disable it for a single line using an inline comment:

Code
1// eslint-disable-next-line @medusajs/middleware-must-call-next2middlewares: [(req, res, next) => { res.json({}) }],