新增属性装饰器演示

src/decorators/validate.ts

@@ -0,0 +1,30 @@
+// 定义一个私有 key
+const requiredMetadataKey = Symbol.for('router:required')
+
+// 定义参数装饰器，大概思路就是把要校验的参数索引保存到成员中
+export const required = function (target, propertyKey: string, parameterIndex: number) {
+  // 属性附加
+  const rules = Reflect.getMetadata(requiredMetadataKey, target, propertyKey) || []
+  rules.push(parameterIndex)
+  Reflect.defineMetadata(requiredMetadataKey, rules, target, propertyKey)
+}
+
+// 定义一个方法装饰器，从成员中获取要校验的参数进行校验
+export const validateEmptyStr = function (target, propertyKey: string, descriptor: PropertyDescriptor) {
+  // 保存原来的方法
+  let method = descriptor.value
+  // 重写原来的方法
+  descriptor.value = function () {
+    let args = arguments
+    // 看看成员里面有没有存的私有的对象
+    const rules = Reflect.getMetadata(requiredMetadataKey, target, propertyKey) as Array<number>
+    if (rules && rules.length) {
+      // 检查私有对象的 key
+      rules.forEach(parameterIndex => {
+        // 对应索引的参数进行校验
+        if (!args[parameterIndex]) throw Error(`arguments${parameterIndex} is invalid`)
+      })
+    }
+    return method.apply(this, arguments)
+  }
+}

src/router.ts

@@ -2,6 +2,7 @@ import { Router } from 'express'
 
 import { symbolHttpMethodsKey, httpGet, httpPost } from './decorators/http-methods'
 import { path, symbolPathKey } from './decorators/path'
+import { required, validateEmptyStr } from './decorators/validate'
 
 class User {
   @httpPost
@@ -15,6 +16,18 @@ class User {
   exit() {
     return 'user logout'
   }
+
+  /**
+   * 属性装饰器演示
+   * @param v1 
+   */
+  @httpGet
+  @path('/validate')
+  @validateEmptyStr
+  valid(@required v1: string) {
+    console.log(v1)
+    return v1
+  }
 }
 
 export default (app: Router) => {