系列文章：
1、async-validator 源码学习（一）：文档翻译
2、async-validator 源码学习笔记（二）：目录结构
rule 主要实现的是校验规则，文件结构为下图：
一、rule 目录文件介绍
其中 index.d.ts 文件：
declare const _default: {
required: import("..").ExecuteRule;
whitespace: import("..").ExecuteRule;
type: import("..").ExecuteRule;
range: import("..").ExecuteRule;
enum: import("..").ExecuteRule;
pattern: import("..").ExecuteRule;
};
export default _default;
是 rule 目录的统一出口管理，主要是给 errors 数组添加对应的 error 。
required.d.ts 文件：
import { ExecuteRule } from '../interface';
declare const required: ExecuteRule;
export default required;
主要作用是校验必填字段的规则。
其中 ExecuteRule 是来自于 interface.d.ts 文件中的
// 摘自其中的一部分 export declare type ExecuteRule = ( rule: InternalRuleItem, value: Value, source: Values, errors: string[], options: ValidateOption, type?: string ) => void; /** * Performs validation for any type. * * @param rule The validation rule. * @param value The value of the field on the source object. * @param callback The callback function. * @param source The source object being validated. * @param options The validation options. * @param options.messages The validation messages. */
ExecuteRule 是统一定义的函数类型别名，统一了函数传递参数和返回值的类型。等价于：
declare const required(rule, value, source, errors, options, type)
方法内的参数及其意义如下：
@param rule 校验的规则
@param value 需要校验字段的当前值
@param source 需要校验的字段
@param errors 本次校验将要去添加的 errors 数组
@param options 校验选项
@param options.message 校验的 messages
type.d.ts
import { ExecuteRule } from '../interface';
declare const type: ExecuteRule;
export default type;
校验值的类型，可能的类型有：integer、float、array、regexp、object、method、email、number、data、url、hex
range.d.ts
import { ExecuteRule } from '../interface';
declare const range: ExecuteRule;
export default range;
校验是否满足最大最小值合理区间的规则
whitespace.d.ts
import { ExecuteRule } from '../interface';
/**
* Rule for validating whitespace.
*
* @param rule The validation rule.
* @param value The value of the field on the source object.
* @param source The source object being validated.
* @param errors An array of errors that this rule may add
* validation errors to.
* @param options The validation options.
* @param options.messages The validation messages.
*/
declare const whitespace: ExecuteRule;
export default whitespace;
校验空白字符的规则
enum.d.ts
import { ExecuteRule } from '../interface';
declare const enumerable: ExecuteRule;
export default enumerable;
校验值是否存在枚举值列表中的规则
pattern.d.ts
import { ExecuteRule } from '../interface';
declare const pattern: ExecuteRule;
export default pattern;
校验正则表达式的规则
二、rule 应用
interface.d.ts 中定义 rule 单元格式
export interface RuleItem {
type?: RuleType; //类型
required?: boolean; //是否为空
pattern?: RegExp | string; //正则
min?: number; // 最小值或长度
max?: number; //最大值或长度
len?: number; // 长度
enum?: Array<string | number | boolean | null | undefined>; //校验值是否存在枚举值列表中的规则
whitespace?: boolean; //是否空白
fields?: Record<string, Rule>;//深度监听属性和规则
options?: ValidateOption;//选项
defaultField?: Rule; //校验属性内部值
transform?: (value: Value) => Value; //校验前转换
message?: string | ((a?: string) => string);//信息提示
//异步校验
asyncValidator?: (rule: InternalRuleItem, value: Value, callback: (error?: string | Error) => void, source: Values, options: ValidateOption) => void | Promise<void>;
//同步校验
validator?: (rule: InternalRuleItem, value: Value, callback: (error?: string | Error) => void, source: Values, options: ValidateOption) => SyncValidateResult | void;
}
// Rule 可以是一个对象，也可以是该对象的数组
export declare type Rule = RuleItem | RuleItem[];
rule 是本字段对应的校验规则：
{
field: "name",
fullField: "name",
message: "姓名为必填项",
required: false,
type: "string",
validator: ƒ required|htmlentities(rule, value, callback, source, options)
}
value 是本字段的值：如小明
source 是要校验的整个 source 对象：
{
name: '小明',
info: {
age: 17,
}
}
errors 是本次校验将要去添加的 errors 数组，假设之前没有 error，则 errors 为[]，如果之前已经存在了一些 error，则格式如下所示：
[
{
message: '年龄超出范围',
field: 'info.age'，
}
]
options 是该字段校验时的选项，当 message 属性为默认值时，格式如下：
{
firstFields: true,
messages: {
array: {len: "%s must be exactly %s in length", min: "%s cannot be less than %s in length", max: "%s cannot be greater than %s in length", range: "%s must be between %s and %s in length"},
clone: ƒ clone(),
date: {format: "%s date %s is invalid for format %s", parse: "%s date could not be parsed, %s is invalid ", invalid: "%s date %s is invalid"},
default: "Validation error on field %s",
enum: "%s must be one of %s",
number: {len: "%s must equal %s", min: "%s cannot be less than %s", max: "%s cannot be greater than %s", range: "%s must be between %s and %s"},
pattern: {mismatch: "%s value %s does not match pattern %s"},
required: "%s is required",
string: {len: "%s must be exactly %s characters", min: "%s must be at least %s characters", max: "%s cannot be longer than %s characters", range: "%s must be between %s and %s characters"},
types: {string: "%s is not a %s", method: "%s is not a %s (function)", array: "%s is not an %s", object: "%s is not an %s", number: "%s is not a %s", …},
whitespace: "%s cannot be empty",
}
}
三、项目开发应用
实际项目开发中验证规则 rule 的写法：
const rules = {
// 深度校验1
address: {
type: 'object',
required: true,
fields: {
//深度校验street属性
street: { type: 'string', required: true },
city: { type: 'string', required: true },
zip: {
type: 'string',
required: true,
len: 8,
message: 'invalid zip',
},
},
},
//校验 2 数组形式
username: [
{
type: 'string',
required: true,
whitespace: true,
transform(value) {
return value.trim()
},
message: '用户名不能为空格',
// 异步校验
asyncValidator: (rule, value) => {
return new Promise((resolve, reject) => {
setTimeout(() => {
if (value != '') {
resolve()
} else {
reject('error')
}
}, 2000)
})
},
},
{
type: 'string',
min: 3,
max: 20,
message: '长度 3- 20 位',
},
],
}