add cors helper

[ianmacartney]

a sketch of what it could look like w.r.t. composition vs. subclassing

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[ianmacartney]

const http = httpRouter();

const httpWithCORS = corsRouter(http, {
  allowedOrigins: ["*"], // allow regex
  allowCredentials: false, // if true, must specify non-* origins
  allowMethods: ["*"],
  allowHeaders: ["*"],
  exposeHeaders: [],
  maxBrowserCacheAge: 600,
});

// route with the one based on what you want.
httpWithCORS.route({
  allowMethods: // overrides
  // normal fields
  path: "/myfn",
  action: "POST",
  handler: myhandler,
});

[sshader]

Can you do things like route to /foo with method GET with CORS and /foo with method POST without CORS? From a quick scan, looks like yes. I guess the OPTIONS will only reflect the ones with the CORS router, which is fine, but also probably not a super common case

[ianmacartney]

Actually that's a bit of a rough edge: I believe if you route w/o CORS, then with CORS, the CORS router will include the non-cors method in the accepted methods

[ianmacartney]

I'll file an issue to track it