Prerequisite: Enable Cross-Origin-isolation

Reason

Since Kùzu does not currently have a fully single-threaded version, the process of compiling Kùzu into Kùzu-wasm using Emscripten requires the use of Pthreads. To support Pthreads, SharedArrayBuffer must be enabled. This means we need to configure the Cross-Origin Opener Policy (COOP) and Cross-Origin Embedder Policy (COEP) headers.

Explaination

Emscripten has support for multithreading using SharedArrayBuffer in browsers. That API allows sharing memory between the main thread and web workers as well as atomic operations for synchronization, which enables Emscripten to implement support for the Pthreads (POSIX threads) API. This support is considered stable in Emscripten.

Note from Emscripten

Browsers that have implemented and enabled SharedArrayBuffer, are gating it behind Cross Origin Opener Policy (COOP) and Cross Origin Embedder Policy (COEP) headers. Pthreads code will not work in deployed environment unless these headers are correctly set. For more information click this

Solution

Modify the COOP/COEP heade.

In your own server: you can control the header

Please refer to cross-origin-isolation-guide

Github Pages

Please refer to coi-serviceworker

Notice

Put coi-serviceworker.js next to your index file

Netlify

netlify.toml template

[[headers]]
for = "/*"
  [headers.values]
    Cross-Origin-Opener-Policy = "same-origin"
    Cross-Origin-Embedder-Policy = "require-corp"
    Access-Control-Allow-Origin = "*"

Vercel

vercel.json template

{
  "headers": [
    {
      "source": "/(.*)",
      "headers": [
        { "key": "Cross-Origin-Opener-Policy", "value": "same-origin" },
        { "key": "Cross-Origin-Embedder-Policy", "value": "require-corp" }
      ]
    }
  ]
}

Express.js

app.use((req, res, next) => {
    res.setHeader("Cross-Origin-Opener-Policy", "same-origin");
    res.setHeader("Cross-Origin-Embedder-Policy", "require-corp");
    next();
});