Slow Array.includes in dev

[hmnd]

Describe the bug

While using #16930 in my project, I noticed that actions which triggered eager effects were taking longer than expected. It seems this array.includes hijack is a major culprit. Perhaps there should be a way for internal function to opt out of these dev mode polyfills?

This identical operation is several orders of magnitude slower time as a result:

with

without

Reproduction

Use array.includes

Logs

System Info

System:
    OS: Linux 5.0 undefined
    CPU: (5) x64 Intel(R) Core(TM) i9-9880H CPU @ 2.30GHz
    Memory: 0 Bytes / 0 Bytes
    Shell: 1.0 - /bin/jsh
  Binaries:
    Node: 20.19.1 - /usr/local/bin/node
    Yarn: 1.22.19 - /usr/local/bin/yarn
    npm: 10.8.2 - /usr/local/bin/npm
    pnpm: 8.15.6 - /usr/local/bin/pnpm
  npmPackages:
    @sveltejs/adapter-auto: ^3.0.0 => 3.3.1 
    @sveltejs/kit: ^2.5.27 => 2.47.1 
    @sveltejs/vite-plugin-svelte: ^5.0.0 => 5.1.1 
    svelte: ^5 => 5.41.0 
    vite: ^6.0.0 => 6.4.0

Severity

annoyance

[7nik]

1. Doing array.includes(...) in a double loop isn't an effective approach in the first place. set.has(..) should be used instead of it.
2. packages/svelte/src/internal/shared/utils.js has some original methods, and includes could be added there, but see 1.

[hmnd]

@7nik I hadn't considered that; fair point!