Registry / aws / aws-lambda-middleware

aws-lambda-middleware

library1.1.2jsnpmunverified

AWS Lambda Middleware is a lightweight library (v1.1.2, last updated 2023) for applying middleware and validating request parameters in AWS Lambda functions. It provides PropTypes for type checking and data correction, a Validate function for custom rules, and supports Express and other frameworks. Key differentiators include minimal overhead for Lambda, deep array/object validation, and customizable error message templates. Release cadence is sporadic, with major changes between v0.9 and v1.0 including reserved prop names, option changes, and required() method replacing isRequired.

aws web-framework

npm install aws-lambda-middleware

github ↗package ↗

INSTALL

IMPORT

SIG · AWS-LAMBDA-MIDDLEW

aws-lambda-middleware

awsjavascriptv1.1.2

harness data pending

Install & Compatibility

Where this runs

No compatibility data collected yet for this library.

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

Middleware

✓ const { Middleware } = require('aws-lambda-middleware')

✗ const Middleware = require('aws-lambda-middleware').Middleware

CommonJS destructuring only; no default export.

Prop

✓ const { Prop } = require('aws-lambda-middleware')

✗ const { PropTypes } = require('aws-lambda-middleware')

Prop is an alias for PropTypes; both work.

Prop.string

✓ Prop.string.required()

✗ Prop.string.isRequired

isRequired deprecated in v1.0; use .required() method.

Creates a Lambda handler with parameter validation using PropTypes and middleware chaining.

const { Middleware, Prop } = require('aws-lambda-middleware') exports.handler = new Middleware().add({ queryStringParameters: { username: Prop.string.required(), age: Prop.integer, friends: [ { name: Prop.string.length({ max: 20 }), gender: Prop.string.or(['male', 'female']) } ] } }).add(async (event, context, prevData) => { const query = event.queryStringParameters console.log(`Hello ${query.username}`) return { statusCode: 200, body: JSON.stringify({ message: 'success' }) } })

Debug

Known issues

breakingv1.0 changes: object and array are reserved prop names, .required() replaces .isRequired, default() uses named parameters, and option() for trim settings.

fix

Update code: use .required() instead of .isRequired, change Prop.*.default(({event}) => {}) to named parameters, use .option({trim: false}) for per-prop trim.

affects: >=1.0.0

breakingv0.9 -> v1.0: interpretation of object and array expressions changed from 'validate only when value exists' to 'required validation'.

fix

Remove required() from object/array props if they should be optional; or add .default() to avoid required validation.

affects: >=1.0.0

deprecated.isRequired is deprecated since v1.0.0.

fix

Replace .isRequired with .required() method.

affects: >=1.0.0

gotchaProp.string.default('') returns undefined if string is empty; fixed in v1.0.4.

fix

Upgrade to v1.0.4 or later.

affects: <1.0.4

gotchaProp.bool.default(false) sets undefined; fixed in v1.0.4.

fix

Upgrade to v1.0.4 or later.

affects: <1.0.4

Errors

Common errors & fixes

TypeError: Prop.string.required is not a function

Using .required without parentheses; should be .required().

fix

Change to Prop.string.required()

Error: Reserved prop name 'object' cannot be overridden

Using 'object' as a prop name is reserved since v1.0.

fix

Rename the prop to something else (e.g., 'params').

TypeError: Cannot destructure property 'event' of 'undefined'

Old syntax for default() with (event) => {} in v1.0+.

fix

Use named parameter object: Prop.string.default(({event}) => event.headers['x-id'])

Upgrade

Version history

1.1.2latest on npm

Audit

Dependencies

No dependency data recorded yet.

Agent activity

21 hits · last 30 days

node

OpenAI (training)

Resources

githubhttps://github.com/blaxk/aws-lambda-middleware ↗

packagehttps://www.npmjs.com/package/aws-lambda-middleware ↗