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Upgrade 4.x -> 5.x

aka "The ESM Only Update"

Version 5.x of Middy no longer supports Node.js versions 16.x. You are highly encouraged to move to Node.js 20.x.

Notable changes​

  • Middy no longer support Common JS modules.
  • Update to use TypeScript v5 along with a refactor to most packages
  • Update all errors to be consistent new Error('message', { cause: { package:'@middy/***', data:*** } })
  • If using multiple http-*-body-parsers on the same endpoint you'll need to set disableContentTypeError:true

Why we deprecated CJS​

  1. ESM has been well supported in Lambda for almost 2 years now
  2. ESM is almost 2x faster than CJS at p95 Using Node.js ES modules and top-level await in AWS Lambda
  3. Maintainability; Maintaining a package to work with every transpilers and build tools that are constantly changing over time is hard and time consuming.

If you're not able to upgrade your codebase to using ESM yet, that's okay, v4.x is super stable and support CJS.

Core​

  • Updated plugin.timeoutEarlyResponse(...) to throw new error with name TimeoutError to match new AbortSignal.timeout().

Util​

No change

Middleware​

appconfig​

  • Update SDK to use newer appconfigdata client Breaking Change

cloudwatch-metrics​

No change

do-not-wait-for-empty-event-loop​

No change

error-logger​

  • Change logger to have request passed in instead of request.error by default to allow access request.context and request.event Breaking Change

event-normalizer​

No change

http-content-encoding​

  • Use preferredLanguage from context instead of event (See http-content-negotiation). Breaking Change

http-content-negotiation​

  • Moved preferred* from event to context Breaking Change

http-cors​

No change

http-error-handler​

  • Will return 500 for all unhandled errors thrown Breaking Change

http-event-normalizer​

  • Will no longer throw an error when HTTP type can't be determined Breaking Change

http-header-normalizer​

No change

http-json-body-parser​

  • Change disableContentTypeError to false by default Breaking Change

http-multipart-body-parser​

  • Change disableContentTypeError to false by default Breaking Change

http-partial-response​

No change

http-response-serializer​

  • Removed parsing of Accept header in favour of using @middy/http-content-negotiation Breaking Change

http-router​

No change

http-security-headers​

No change

http-urlencode-body-parser​

  • Change disableContentTypeError to false by default Breaking Change

http-urlencode-path-parser​

No change

input-output-logger​

  • Updated to use structuredClone

rds-signer​

No change

s3-object-response​

  • Refactored to use fetch over https. context now returns s3ObjectFetch to allow more control over how it's used. Breaking Change

secrets-manager​

No change

service-discovery​

No change

sqs-partial-batch-failure​

  • Will now catch unhandled errors and set all messages to failed, preventing infinite loops Breaking Change

ssm​

No change

sts​

No change

validator​

  • Use preferredLanguage from context instead of event (See http-content-negotiation).
  • ajv-cmd is no longer a required dependency, if you're pre-transpiling you'll need to run npm i ajv-cmd.

warmup​

No change

ws-json-body-parser​

  • Remove inclusion of rawBody from event Breaking Change

ws-response​

No change

ws-router​

No change

Notes​

None