如何在Zod Error Map中实现自定义必填项错误提示？

问题描述 #

想要实现Zod错误映射的自定义消息，但不清楚如何在错误映射中统一设置必填项提示（required_message），因为ZodIssueCode枚举里找不到对应的代码，此前只能在每个schema字段中手动设置。

当前错误映射代码：

const customErrorMap: z.ZodErrorMap = (issue, ctx) => {
    switch (issue.code) {
        case z.ZodIssueCode.invalid_type:
            if (issue.expected === "string") {
                return { message: 'invalid_string' };
            } else if (issue.expected === "number") {
                return { message: 'invalid_number' };
            } else {
                return { message: 'invalid_type' };
            }
        case z.ZodIssueCode.custom:
            return { message: issue.message || 'custom_error' };
        case z.ZodIssueCode.invalid_union:
            return { message: 'invalid_union' };
        case z.ZodIssueCode.invalid_enum_value:
            return { message: 'invalid_enum_value' };
        case z.ZodIssueCode.unrecognized_keys:
            return { message: 'unrecognized_keys' };
        case z.ZodIssueCode.invalid_arguments:
            return { message: 'invalid_arguments' };
        case z.ZodIssueCode.invalid_return_type:
            return { message: 'invalid_return_type' };
        case z.ZodIssueCode.invalid_date:
            return { message: 'invalid_date' };
        case z.ZodIssueCode.invalid_string:
            return { message: 'invalid_string' };
        case z.ZodIssueCode.too_small:
            return { message: 'too_small' };
        case z.ZodIssueCode.too_big:
            return { message: 'too_big' };
        case z.ZodIssueCode.invalid_intersection_types:
            return { message: 'invalid_intersection_types' };
        case z.ZodIssueCode.not_multiple_of:
            return { message: 'not_multiple_of' };
        case z.ZodIssueCode.not_finite:
            return { message: 'not_finite' };
        default:
            return { message: ctx.defaultError };
    }
}

ZodIssueCode定义：

export declare const ZodIssueCode: {
invalid_type: "invalid_type";
invalid_literal: "invalid_literal";
custom: "custom";
invalid_union: "invalid_union";
invalid_union_discriminator: "invalid_union_discriminator";
invalid_enum_value: "invalid_enum_value";
unrecognized_keys: "unrecognized_keys";
invalid_arguments: "invalid_arguments";
invalid_return_type: "invalid_return_type";
invalid_date: "invalid_date";
invalid_string: "invalid_string";
too_small: "too_small";
too_big: "too_big";
invalid_intersection_types: "invalid_intersection_types";
not_multiple_of: "not_multiple_of";
not_finite: "not_finite";
};

解决方案 #

Zod没有单独的必填项IssueCode，必填字段缺失的错误会归类到invalid_type，此时issue.received的值为undefined，issue.expected为该字段预期的类型（如string、number等）。

只需在invalid_type分支中优先判断received是否为undefined，返回自定义必填提示即可，修改后的错误映射代码如下：

const customErrorMap: z.ZodErrorMap = (issue, ctx) => {
    switch (issue.code) {
        case z.ZodIssueCode.invalid_type:
            // 处理必填项缺失场景
            if (issue.received === undefined) {
                return { message: '此字段为必填项' };
            }
            // 原有类型不匹配判断逻辑
            if (issue.expected === "string") {
                return { message: '请输入有效的字符串' };
            } else if (issue.expected === "number") {
                return { message: '请输入有效的数字' };
            } else {
                return { message: '类型不匹配' };
            }
        case z.ZodIssueCode.custom:
            return { message: issue.message || '自定义错误' };
        case z.ZodIssueCode.invalid_union:
            return { message: '无效的联合类型' };
        case z.ZodIssueCode.invalid_enum_value:
            return { message: '无效的枚举值' };
        case z.ZodIssueCode.unrecognized_keys:
            return { message: '存在未识别的字段' };
        case z.ZodIssueCode.invalid_arguments:
            return { message: '无效的参数' };
        case z.ZodIssueCode.invalid_return_type:
            return { message: '无效的返回类型' };
        case z.ZodIssueCode.invalid_date:
            return { message: '无效的日期格式' };
        case z.ZodIssueCode.invalid_string:
            return { message: '无效的字符串格式' };
        case z.ZodIssueCode.too_small:
            return { message: '值过小' };
        case z.ZodIssueCode.too_big:
            return { message: '值过大' };
        case z.ZodIssueCode.invalid_intersection_types:
            return { message: '无效的交叉类型' };
        case z.ZodIssueCode.not_multiple_of:
            return { message: '不是指定倍数' };
        case z.ZodIssueCode.not_finite:
            return { message: '不是有限数值' };
        default:
            return { message: ctx.defaultError };
    }
}

最后设置全局错误映射生效：

z.setErrorMap(customErrorMap);

这样就能统一处理所有必填字段的缺失提示，无需再逐个字段手动设置。

内容的提问来源于stack exchange，提问作者steve123