Typescript incompatible type in 3.1.0 and Express 4.x

[aabrams]

Trying to add in Express 4.x middleware:

import { Receiver, CloudEvent } from "cloudevents";

const receivedEvent: CloudEvent = Receiver.accept(req.headers, req.body);

It fails with:

(property) IncomingMessage.headers: IncomingHttpHeaders
Argument of type 'IncomingHttpHeaders' is not assignable to parameter of type 'Headers'.
Index signatures are incompatible.
Type 'string | string[]' is not assignable to type 'string'.
Type 'string[]' is not assignable to type 'string'.ts(2345)

[lance]

It appears that the IncomingHttpHeaders type is from Node core, so I think this will probably be a common issue. We should consider modifying our type.

sdk-javascript/src/message/index.ts

Lines 21 to 23 in 1fa3a05

	export interface Headers {
	[key: string]: string;
	}

In the meantime @aabrams can you try

const receivedEvent: CloudEvent = Receiver.accept(req.headers as Headers, req.body);

[aabrams]

Trying what you suggested (req.headers as Headers):

Argument of type 'Headers' is not assignable to parameter of type 'import("c:/Users/adam_a/repos/Segment-Webhook/node_modules/cloudevents/dist/transport/http/headers").Headers'.
Index signature is missing in type 'Headers'.ts(2345)
Conversion of type 'IncomingHttpHeaders' to type 'Headers' may be a mistake because neither type sufficiently overlaps with the other. If this was intentional, convert the expression to 'unknown' first.ts(2352)
Conversion of type 'IncomingHttpHeaders' to type 'Headers' may be a mistake because neither type sufficiently overlaps with the other. If this was intentional, convert the expression to 'unknown' first.
Type 'IncomingHttpHeaders' is missing the following properties from type 'Headers': append, delete, get, has, and 6 more.ts(2352)