[Bug]: Should not lower function default parameters when using `syntax: 'es2021'

[chenjiahan]

Version

Rslib 0.0.11

Details

• Rslib config:

export default {
  lib: [
    {
      format: 'esm',
      syntax: 'es2021',
    },
  ],
  output: {
    target: 'node',
  },
};

• Input:

export function foo(options: unknown = {}): void {
  console.log(options);
}

• Current output:

function foo() {
    let options = arguments.length > 0 && void 0 !== arguments[0] ? arguments[0] : {};
    console.log(options);
}
export { foo };

• Expected output:

function foo(options = {}) {
    console.log(options);
}
export { foo };

Reproduce link

I found this issue in some Rsbuild packages

Reproduce Steps

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