middy.js. ERROR: Middleware must be an object containing at least one key among "before", "after", "onError"

Question

I'm trying to get started with Middy to validate input schema on AWS lambda.

The lambda function below keeps throwing this error:

Middleware must be an object containing at least one key among "before", "after", "onError"

Anyone knows what could be the issue?

I'm running

     Node v18.12.1
    "@middy/core": "^4.0.2",
    "@middy/http-error-handler": "^4.0.2",
    "@middy/http-json-body-parser": "^4.0.2",
    "@middy/validator": "^4.0.2",

here is the lambda code

import middy from "@middy/core";
import validator from "@middy/validator";
import httpErrorHandler from "@middy/http-error-handler";
import jsonBodyParser from "@middy/http-json-body-parser";


const baseHandler = (event) => {
    const { fname, lname } = event.body;
    return {
      statusCode: 200,
      headers: { "Content-Type": "text/plain" },
      body: `Hello, ${fname}-${lname}.`,
    };
  };

const inputSchema = {
    type: "object",
    properties: {
      body: {
        type: "object",
        properties: {
          fname: { type: "string" },
          lname: { type: "string" },
        },
        required: ["fname", "lname"],
      },
    },
  };

const handler = middy(baseHandler)
    .use(jsonBodyParser())
    .use(
        validator({
        inputSchema,
        })
    )
    .use(httpErrorHandler());

export { handler };

I expected that the validator throws an error when the input parameters are not provided to the function

Answer 1

thanks Will Farrell

Change inputSchema to eventSchema. The name was changed in v3, and fully removed in v4.

See: https://middy.js.org/docs/upgrade/3-4

view it on GitHub