TypeScript AWS Lambda micro-framework

• Supports AWS Gateway API V2
• Tested with Node 20+
• Vitest test framework with basic I/O simulator

Todo

• Implement; S3, DynamoDB
• Dev server

What does it do?

Provides a basic HTTP path routing system, for example GET /product/foo

import { create } from 'lambda.ts';

/** Shared function logic here... */

const λ = create();
λ.route('/product/[s:%s]').get((Δ) => {
	return λ.response(Δ.pathData).json(); // { s: 'foo' }
});

export const handler = λ.handler;

Provides first-class HTTP verb helpers on routes; GET/POST/PUT/PATCH/DELETE:

λ.route('/product/[s:%s]').delete((Δ) => {
	return λ.response().code(204).basic();
});

Middleware wraps the Lambda handler (including 404/500). CORS can be enabled on create() or via λ.use(cors()):

import { create } from 'lambda.ts';

const λ = create({ cors: true }); // origin: "*"
λ.use(async (_ctx, next) => {
	const result = await next();
	return result;
});

λ.route('/product/[s:%s]').get((Δ) => {
	return λ.response(Δ.pathData).json();
});

export const handler = λ.handler;

import { create, cors } from 'lambda.ts';

const λ = create();
λ.use(cors({
	origin: 'https://app.example.com',
	credentials: true,
}));

...will provide S3 object manipulation

import { create } from 'lambda.ts';

const λ = create();
λ.route('/').get(async () => {
	const obj = await λ.object('/foo/bar');
	const result = obj.value();
	if (!result) return λ.response('Oops!').code(500).text();
	return λ.response(result).json();
});

export const handler = λ.handler;

...will provide key/value storage, with option to persist via DynamoDB

import { create } from 'lambda.ts';
import { DynamoDBClient } from "@aws-sdk/client-dynamodb";

const λ = create();
λ.route('/').get(async () => {
	try {
		const foo = await λ.key('foo', { persist: true, table: 'bar' });
		return λ.response(await foo.value()).json();
	} catch (error) {
		return λ.response('Oops!').code(500).text();
	}
});

export const handler = λ.handler;

Testing

npx vitest tests

Provides a basic AWS Gateway API invocation simulator, where you write tests as...

import { describe, it, expect } from "vitest";
import { simulator } from "./simulator";
import { handler } from "./lambda/example";

const result = await simulator(handler, {
	method: "GET",
	path: "/doesnt-exist"
});

expect(result.statusCode).toBe(404);
expect(result.body).toBeUndefined();

Development

Local server to be implemented