[aws-lambda] Potentially incorrect API Gateway Proxy types?

[ralbertazzi]

DefinitelyTyped/types/aws-lambda/trigger/api-gateway-proxy.d.ts

Lines 111 to 133 in b8d1466

	export interface APIGatewayProxyEventHeaders {
	[name: string]: string | undefined;
	}
	export interface APIGatewayProxyEventMultiValueHeaders {
	[name: string]: string[] | undefined;
	}
	export interface APIGatewayProxyEventPathParameters {
	[name: string]: string | undefined;
	}
	export interface APIGatewayProxyEventQueryStringParameters {
	[name: string]: string | undefined;
	}
	export interface APIGatewayProxyEventMultiValueQueryStringParameters {
	[name: string]: string[] | undefined;
	}
	export interface APIGatewayProxyEventStageVariables {
	[name: string]: string | undefined;
	}

The current type definitions of the linked types assumes that a value can be present but have undefined value:

[name: string]: string | undefined

// the same as [name: string]: (string | undefined)

It feels weird that, for example, queryParameters can be present, have an actual entry, but have such value undefined. I wonder instead if the goal was to define such types differently, signaling that an event property can either be defined (and have all non-null values) or undefined

{ [name: string]: string } | undefined

Even better, since most of those types are then part of other Event types in the form of TheType | null or param? : TheType I would even be tempted to believe that this should be the correct type:

[name: string]: string

Let me know if you agree. If so, I'd gladly provide a pull request fixing it

[jelder]

Agree that something is missing. This code for example requires the @ts-expect-error but also prints the query string.

export const connect: APIGatewayProxyWebsocketHandlerV2 = async (event) => {
  // @ts-expect-error queryStringParameters exists in reality
  console.log(JSON.stringify(event.queryStringParameters, null, 2))
  return {
    statusCode: 200,
    body: "connected",
  };
};