fix: any response headers from SvelteKit are not passed to express on Node.js v16 runtime

[co3k]

Summary

changed to pass headers value as an Array of headers to express.Response#writeHead(...)

Fixes: #165

[jthegedus]

Are you able to debug the error?

[hosting] Rewriting /about to http://localhost:5001/demo/us-central1/sveltekit for local Function us-central1/sveltekit
i  functions: Beginning execution of "sveltekit"
>  {"severity":"INFO","message":"Initialising SvelteKit SSR Handler"}
>  {"severity":"INFO","message":"SvelteKit SSR Handler initialised!"}
>  {"severity":"INFO","message":"Requested resource: /about"}
⚠  functions: TypeError [ERR_INVALID_HTTP_TOKEN]: Header name must be a valid HTTP token ["[ 'content-type', 'text/html' ]"]
    at ServerResponse.setHeader (node:_http_outgoing:578:3)
    at ServerResponse.writeHead (node:_http_server:300:21)
    at svelteKit (/tmp/svelte-adapter-firebase-LfHV/functions/sveltekit/index.js:8671:30)
    at processTicksAndRejections (node:internal/process/task_queues:96:5)
    at async runFunction (/tmp/svelte-adapter-firebase-LfHV/node_modules/firebase-tools/lib/emulator/functionsEmulatorRuntime.js:564:9)
    at async runHTTPS (/tmp/svelte-adapter-firebase-LfHV/node_modules/firebase-tools/lib/emulator/functionsEmulatorRuntime.js:590:5)
    at async handler (/tmp/svelte-adapter-firebase-LfHV/node_modules/firebase-tools/lib/emulator/functionsEmulatorRuntime.js:510:17)

I won't be able to get to this for a few days

[Nushio]

Hi Kousuke!

rendered.headers ?? []

Does what you're trying to accomplish, as rendered.headers is already an array.

[timstrucken]

Hello to you all! :) I created a new PR (#176 ) which fixed the issue for me. When using this fix, the TypeError exception was raised just like @jthegedus already commented

[jthegedus]

fixed in #176