trim,toLowerCase转换在zod中不起作用

import { z } from "zod";

const signupSchema = z.object({
    name: z
        .string({
            required_error: "Please provide your name",
            invalid_type_error: "Your name must be a string",
        })
        .min(3, { message: "Your name must be atleast 3 characters long" })
        .max(32, { message: "Your name cannot exceed 32 characters" })
        .trim(),
    username: z
        .string({
            required_error: "Please provide your username",
            invalid_type_error: "Username must be a string",
        })
        .min(3, { message: "Username must be atleast 3 characters long" })
        .max(32, { message: "Username cannot exceed 32 characters" })
        .trim()
        .toLowerCase(),
    email: z
        .string({
            required_error: "Please provide your email",
            invalid_type_error: "Email must be a string",
        })
        .email({ message: "Please provide a valid email address" })
        .trim()
        .toLowerCase(),
    password: z
        .string({
            required_error: "Please provide your password",
            invalid_type_error: "Password must be a string",
        })
        .min(8, { message: "Password must be atleast 8 characters long" })
        .regex(/(?=.*\d)(?=.*[a-z])(?=.*[A-Z])(?=.*\W)/gm, {
            message:
                "Password must include at least one uppercase letter, one lowercase letter, one digit and one special character",
        }),
    bio: z
        .string({ invalid_type_error: "Bio must be a string" })
        .max(256, { message: "Bio cannot exceed 256 characters" })
        .trim()
        .optional(),
});

export { signupSchema };

我用它来验证请求,验证工作正常,但trim()、toLowerCase()等转换不起作用。我正在使用wait-signaupSchema.parseAsync(body)。请帮帮我