Switch 控制节点

概述

Switch控制节点是一个多分支条件处理节点，根据表达式计算结果将数据路由到不同的分支执行。它支持复杂的条件判断和多种匹配模式，是实现复杂业务逻辑分支的核心控制节点。

节点配置

基本属性

{
  "id": "switch-1",
  "type": "control",
  "config": {
    "identifier": "switch",
    "title": "条件分支器",
    "description": "多分支条件处理"
  }
}

输入参数

参数名	类型	必填	描述
data	Object/Any	✅	输入数据，用于表达式计算
expression	String	✅	条件表达式，支持JavaScript表达式
cases	Array	✅	分支案例数组，每个案例包含value和port
defaultCase	Object	❌	默认分支，当没有匹配的case时执行

分支案例结构

{
  "cases": [
    {
      "value": "A",           // 匹配值
      "port": "gradeA"        // 输出端口名
    },
    {
      "value": ["VIP", "GOLD"], // 支持数组匹配
      "port": "premium"
    }
  ],
  "defaultCase": {
    "port": "default"         // 默认端口
  }
}

表达式计算

Switch节点使用ConditionEvaluator来计算表达式，支持：

基本表达式

// 简单属性访问
"data.score"
"data.user.level"

// 数值比较
"data.score >= 90"
"data.amount > 1000"

// 字符串匹配
"data.status === 'active'"
"data.type"

复合表达式

// 三元运算符
"data.score >= 90 ? 'A' : data.score >= 80 ? 'B' : 'C'"

// 逻辑运算
"data.amount > 1000 && data.customer.vip"
"data.type === 'URGENT' || data.priority === 'HIGH'"

// 复杂条件组合
"data.amount > 1000 && data.customer.vip ? 'VIP_LARGE' : data.type === 'URGENT' ? 'URGENT' : 'NORMAL'"

匹配模式

Switch节点支持三种匹配模式：

1. 精确匹配

{
  "cases": [
    { "value": "A", "port": "excellent" },
    { "value": "B", "port": "good" },
    { "value": 90, "port": "highScore" }
  ]
}

2. 字符串匹配（忽略大小写）

{
  "cases": [
    { "value": "pending", "port": "waitingHandler" },
    { "value": "RUNNING", "port": "activeHandler" }
  ]
}
// "PENDING" 和 "pending" 都会匹配到 waitingHandler

3. 数组包含匹配

{
  "cases": [
    { "value": ["DIAMOND", "PLATINUM", "GOLD"], "port": "premium" },
    { "value": ["SILVER", "BRONZE"], "port": "standard" }
  ]
}
// data.level 为 "GOLD" 时会匹配到 premium 端口

上下文管理

Switch节点会在上下文中保存执行结果：

// 上下文结构
context['switch-1'] = {
  [matchedPort]: inputData,    // 匹配的端口对应的数据
  '_switch_result': {
    expression: "data.score >= 90 ? 'A' : 'B'",
    expressionValue: "A",      // 表达式计算结果
    matchedCase: "A",          // 匹配的案例值
    matchedPort: "gradeA"      // 匹配的端口名
  }
}

使用示例

示例1：成绩评级系统

{
  "nodes": {
    "score-processor": {
      "type": "operator",
      "config": {
        "operator": "jsexecutor",
        "code": "const student = { name: '张三', score: 95, subject: '数学' }; return student;"
      }
    },
    "grade-switch": {
      "type": "control",
      "config": {
        "identifier": "switch"
      }
    },
    "excellent-handler": {
      "type": "operator",
      "config": {
        "operator": "jsexecutor",
        "code": "return { result: 'excellent', message: `恭喜${parameters.name}！成绩优秀（${parameters.score}分）`, grade: 'A' };"
      }
    },
    "good-handler": {
      "type": "operator",
      "config": {
        "operator": "jsexecutor",
        "code": "return { result: 'good', message: `${parameters.name}成绩良好（${parameters.score}分）`, grade: 'B' };"
      }
    },
    "pass-handler": {
      "type": "operator",
      "config": {
        "operator": "jsexecutor",
        "code": "return { result: 'pass', message: `${parameters.name}成绩及格（${parameters.score}分）`, grade: 'C' };"
      }
    },
    "fail-handler": {
      "type": "operator",
      "config": {
        "operator": "jsexecutor",
        "code": "return { result: 'fail', message: `${parameters.name}成绩不及格（${parameters.score}分）`, grade: 'D' };"
      }
    }
  },
  "edges": [
    {
      "source": "score-processor",
      "target": "grade-switch",
      "sourcePort": "result",
      "targetPort": "data"
    },
    {
      "source": "grade-switch",
      "target": "excellent-handler",
      "sourcePort": "gradeA",
      "targetPort": "parameters"
    },
    {
      "source": "grade-switch",
      "target": "good-handler",
      "sourcePort": "gradeB",
      "targetPort": "parameters"
    },
    {
      "source": "grade-switch",
      "target": "pass-handler",
      "sourcePort": "gradeC",
      "targetPort": "parameters"
    },
    {
      "source": "grade-switch",
      "target": "fail-handler",
      "sourcePort": "default",
      "targetPort": "parameters"
    }
  ],
  "inputs": {
    "grade-switch": {
      "expression": "data.score >= 90 ? 'A' : data.score >= 80 ? 'B' : data.score >= 60 ? 'C' : 'D'",
      "cases": [
        { "value": "A", "port": "gradeA" },
        { "value": "B", "port": "gradeB" },
        { "value": "C", "port": "gradeC" }
      ],
      "defaultCase": { "port": "default" }
    }
  }
}

示例2：客户等级服务分派

{
  "nodes": {
    "customer-analyzer": {
      "type": "operator",
      "config": {
        "operator": "jsexecutor",
        "code": "const customer = { id: 'C001', name: '张总', level: 'DIAMOND', region: 'CN', spending: 50000 }; return customer;"
      }
    },
    "service-router": {
      "type": "control",
      "config": {
        "identifier": "switch"
      }
    },
    "vip-service": {
      "type": "operator",
      "config": {
        "operator": "jsexecutor",
        "code": "return { type: 'premium_service', message: `尊敬的${parameters.name}，您享受VIP专属服务`, level: parameters.level, benefits: ['专属客服', '优先处理', '特殊折扣'] };"
      }
    },
    "standard-service": {
      "type": "operator",
      "config": {
        "operator": "jsexecutor",
        "code": "return { type: 'standard_service', message: `亲爱的${parameters.name}，感谢您的支持`, level: parameters.level, benefits: ['标准服务'] };"
      }
    },
    "basic-service": {
      "type": "operator",
      "config": {
        "operator": "jsexecutor",
        "code": "return { type: 'basic_service', message: `${parameters.name}，欢迎使用我们的服务` };"
      }
    }
  },
  "edges": [
    {
      "source": "customer-analyzer",
      "target": "service-router",
      "sourcePort": "result",
      "targetPort": "data"
    },
    {
      "source": "service-router",
      "target": "vip-service",
      "sourcePort": "premium",
      "targetPort": "parameters"
    },
    {
      "source": "service-router",
      "target": "standard-service",
      "sourcePort": "standard",
      "targetPort": "parameters"
    },
    {
      "source": "service-router",
      "target": "basic-service",
      "sourcePort": "default",
      "targetPort": "parameters"
    }
  ],
  "inputs": {
    "service-router": {
      "expression": "data.level",
      "cases": [
        { "value": ["DIAMOND", "PLATINUM", "GOLD"], "port": "premium" },
        { "value": ["SILVER", "BRONZE"], "port": "standard" }
      ],
      "defaultCase": { "port": "default" }
    }
  }
}

示例3：订单处理分派

{
  "nodes": {
    "order-classifier": {
      "type": "operator",
      "config": {
        "operator": "jsexecutor",
        "code": "const order = { id: 'O001', amount: 1500, type: 'URGENT', priority: 'HIGH', customer: { vip: true } }; return order;"
      }
    },
    "order-switch": {
      "type": "control",
      "config": {
        "identifier": "switch"
      }
    },
    "vip-order-handler": {
      "type": "operator",
      "config": {
        "operator": "jsexecutor",
        "code": "return { type: 'vip_large_order', message: `VIP大额订单 ${parameters.id} 优先处理`, amount: parameters.amount, fast_track: true };"
      }
    },
    "urgent-order-handler": {
      "type": "operator",
      "config": {
        "operator": "jsexecutor",
        "code": "return { type: 'urgent_order', message: `紧急订单 ${parameters.id} 加急处理`, priority: parameters.priority };"
      }
    },
    "normal-order-handler": {
      "type": "operator",
      "config": {
        "operator": "jsexecutor",
        "code": "return { type: 'normal_order', message: `订单 ${parameters.id} 正常处理` };"
      }
    }
  },
  "edges": [
    {
      "source": "order-classifier",
      "target": "order-switch",
      "sourcePort": "result",
      "targetPort": "data"
    },
    {
      "source": "order-switch",
      "target": "vip-order-handler",
      "sourcePort": "vipLarge",
      "targetPort": "parameters"
    },
    {
      "source": "order-switch",
      "target": "urgent-order-handler",
      "sourcePort": "urgent",
      "targetPort": "parameters"
    },
    {
      "source": "order-switch",
      "target": "normal-order-handler",
      "sourcePort": "normal",
      "targetPort": "parameters"
    }
  ],
  "inputs": {
    "order-switch": {
      "expression": "data.amount > 1000 && data.customer.vip ? 'VIP_LARGE' : data.type === 'URGENT' ? 'URGENT' : 'NORMAL'",
      "cases": [
        { "value": "VIP_LARGE", "port": "vipLarge" },
        { "value": "URGENT", "port": "urgent" },
        { "value": "NORMAL", "port": "normal" }
      ]
    }
  }
}

示例4：状态机处理

{
  "nodes": {
    "task-monitor": {
      "type": "operator",
      "config": {
        "operator": "jsexecutor",
        "code": "const task = { id: 'task-001', status: 'pending', priority: 'high' }; return task;"
      }
    },
    "status-router": {
      "type": "control",
      "config": {
        "identifier": "switch"
      }
    },
    "pending-handler": {
      "type": "operator",
      "config": {
        "operator": "jsexecutor",
        "code": "return { result: 'pending_handled', message: `任务${parameters.id}等待处理`, nextStatus: 'running' };"
      }
    },
    "running-handler": {
      "type": "operator",
      "config": {
        "operator": "jsexecutor",
        "code": "return { result: 'running_handled', message: `任务${parameters.id}正在执行`, progress: 50 };"
      }
    },
    "completed-handler": {
      "type": "operator",
      "config": {
        "operator": "jsexecutor",
        "code": "return { result: 'completed_handled', message: `任务${parameters.id}已完成`, completedAt: new Date().toISOString() };"
      }
    },
    "error-handler": {
      "type": "operator",
      "config": {
        "operator": "jsexecutor",
        "code": "return { result: 'error_handled', message: `任务${parameters.id}状态异常`, needsReview: true };"
      }
    }
  },
  "edges": [
    {
      "source": "task-monitor",
      "target": "status-router",
      "sourcePort": "result",
      "targetPort": "data"
    },
    {
      "source": "status-router",
      "target": "pending-handler",
      "sourcePort": "pending",
      "targetPort": "parameters"
    },
    {
      "source": "status-router",
      "target": "running-handler",
      "sourcePort": "running",
      "targetPort": "parameters"
    },
    {
      "source": "status-router",
      "target": "completed-handler",
      "sourcePort": "completed",
      "targetPort": "parameters"
    },
    {
      "source": "status-router",
      "target": "error-handler",
      "sourcePort": "default",
      "targetPort": "parameters"
    }
  ],
  "inputs": {
    "status-router": {
      "expression": "data.status",
      "cases": [
        { "value": "pending", "port": "pending" },
        { "value": "running", "port": "running" },
        { "value": "completed", "port": "completed" }
      ],
      "defaultCase": { "port": "default" }
    }
  }
}

错误处理

表达式计算失败时的回退机制

// 1. 首先尝试使用ConditionEvaluator计算表达式
// 2. 如果失败，尝试将表达式作为属性名从inputData中获取值
// 3. 最后回退到直接使用表达式本身作为值

无匹配分支时的处理

// 如果没有匹配的case且没有defaultCase，返回null，不执行任何分支
if (!matchedPort) {
  console.log('没有匹配的分支需要执行');
  return null;
}

最佳实践

1. 表达式设计建议

// ✅ 推荐：清晰的逻辑结构
"data.score >= 90 ? 'A' : data.score >= 80 ? 'B' : 'C'"

// ✅ 推荐：组合多个条件
"data.amount > 1000 && data.customer.vip"

// ✅ 推荐：简单属性访问
"data.status"
"data.user.level"

2. 分支设计模式

// 分级处理模式
{
  "cases": [
    { "value": ["LEVEL_1", "LEVEL_2"], "port": "highLevel" },
    { "value": ["LEVEL_3", "LEVEL_4"], "port": "midLevel" },
    { "value": ["LEVEL_5"], "port": "lowLevel" }
  ],
  "defaultCase": { "port": "defaultLevel" }
}

// 状态机模式
{
  "cases": [
    { "value": "INIT", "port": "initialize" },
    { "value": "PROCESSING", "port": "process" },
    { "value": "COMPLETE", "port": "finalize" }
  ],
  "defaultCase": { "port": "error" }
}

3. 调试技巧

// 在子工作流中访问Switch的决策信息
const processor = `
  const switchResult = context['switch-1']._switch_result;
  console.log('Switch决策信息:', {
    expression: switchResult.expression,
    value: switchResult.expressionValue,
    matchedCase: switchResult.matchedCase,
    port: switchResult.matchedPort
  });
  
  return { 
    processed: parameters,
    decision: switchResult
  };
`;

4. 性能优化

// 将最常用的case放在前面
{
  "cases": [
    { "value": "COMMON_STATUS", "port": "commonHandler" },    // 90%的情况
    { "value": "RARE_STATUS", "port": "rareHandler" },        // 10%的情况
    { "value": "VERY_RARE", "port": "specialHandler" }        // 1%的情况
  ]
}

重要说明：Switch节点作为纯控制节点，根据条件选择执行路径后会停止主工作流的后续执行，所有的业务逻辑都在选中的分支子工作流中完成。