`swc` transforms decorators when target: "esnext" (inconsistent with `tsc`)

[yanjiew1]

Describe the bug

Currently, swc transforms decorators even when the output target is explicitly set to esnext. This behavior deviates from tsc (verified up to version 6.0.2), which leaves decorators intact under the esnext target.

Input code

function decorator() {}

@decorator
class someclass {

    @decorator
    somemethod(){}
}

Config

{
  "jsc": {
    "parser": {
      "syntax": "ecmascript",
      "decorators": true
    },
    "transform": {
        "decoratorVersion": "2022-03"
    },
    "target": "esnext"
  }
}

Link to the code that reproduces this issue

https://play.swc.rs/?version=1.15.24&code=H4sIAAAAAAAAA0srzUsuyczPU0hJTc4vSizJL9LQVKiu5eJygAtwJeckFhcrFOfnpkJY1VxcCkCApALEBcnnppZk5KdoaAINqOUCAMy8AmRbAAAA&config=H4sIAAAAAAAAA1WNwQqDQAxE737FknMFWW%2F9kN7DNi0K7sokBYvsvzdaLPaWmZeZWZsQaNRE17D66WJmqOCn3dF3Nl7cIUkTa8IwG10OepdUwFag%2FmF4yQ7ql5OBsz4KplPhOXQT6FDyVh67GNuup%2F884ym2b2uWxTZam%2FoBjEo2B7cAAAA%3D

SWC Info output

Operating System:
    Platform: win32
    Arch: x64
    Machine Type: x86_64
    Version: Windows 11 Pro
    CPU: (16 cores)
        Models: AMD Ryzen 7 7840U w/ Radeon  780M Graphics

Binaries:
    Node: 25.6.0
    npm: N/A
    Yarn: N/A
    pnpm: N/A

Relevant Packages:
    @swc/core: 1.15.24
    @swc/helpers: N/A
    @swc/types: 0.1.26
    typescript: 6.0.2

SWC Config:
    output: N/A
    .swcrc path: N/A

Next.js info:
    output: N/A

Expected behavior

When target is set to "esnext", decorators should not be transformed, mirroring the behavior of tsc.

Actual behavior

Decorators are being transformed, regardless of the esnext target.

Version

1.15.24

Additional context

No response