Array parameters are JSON-encoded instead of using repeated query parameters

[renjianguo666]

Current Behavior
When I use navigate() with an array value in search params, TanStack Router serializes it as JSON:

// Code
navigate({
  search: { role: ["admin", "member"] }
})

// Current URL result
?role=%5B"admin"%2C"member"%5D
// Which decodes to: role=["admin","member"]

Expected Behavior
I expect array parameters to use repeated query parameters (standard HTTP convention):

?role=admin&role=member

My Setup
Schema definition:

const searchSchema = z.object({
  page: z.number().catch(1),
  role: z.enum(['admin', 'member', 'vip']).array().optional(),
})

export const Route = createFileRoute('/hello')({
  validateSearch: searchSchema,
})

Why I Need This
Backend compatibility: My API expects ?role=admin&role=member, not JSON-encoded arrays

[schiller-manuel]

https://tanstack.com/router/latest/docs/framework/react/guide/custom-search-param-serialization#using-the-query-string-library