- 简介
- 入门指南
- 使用 BPMN 进行流程建模
- 使用 案例管理 进行流程建模
- Process modeling with Flow
- 入门指南
- 核心概念
- Node reference
- Build guides
- 最佳实践
- 参考
- 流程实施
- 流程运营
- 流程监控
- 流程优化
- 参考信息
Maestro 用户指南
操作
Runs JavaScript code and passes the return value to downstream nodes.
Configuration reference
| 字段 | 必填 | 默认 | 描述 |
|---|---|---|---|
| 脚本 | 是 | 无 | JavaScript code to execute. Must contain a return statement; the returned value becomes this node's output. |
The JavaScript environment
Scripts run in an isolated runtime and have access to:
$vars— the flow's variable scope. Access upstream node output via$vars.<nodeName>.<property>.metadata— flow execution metadata- Standard JavaScript built-ins — such as
JSON,Math,Date,Array,Object,String,Number,RegExp,Error,Promise,URL,URLSearchParams, and the timer functions.
For security, the runtime blocks network APIs (fetch, XMLHttpRequest, WebSocket), dynamic code execution (eval, Function), and storage APIs (indexedDB, caches). To call an external API, use the HTTP Request node instead.
Scripts are meant for fast, in-memory logic: keep them quick and avoid processing very large payloads, which can exceed runtime limits or time out.
Accessing upstream node output
Use $vars.<nodeName>.<property> where <nodeName> is the node's variable name (shown in the properties panel):
// Access HTTP Request node response
const body = $vars.httpRequest1.output.body;
const status = $vars.httpRequest1.output.statusCode;
// Access a flow variable
const count = $vars.myVariable;
// Access HTTP Request node response
const body = $vars.httpRequest1.output.body;
const status = $vars.httpRequest1.output.statusCode;
// Access a flow variable
const count = $vars.myVariable;
返回值
The script must return a value. The returned value becomes the node's output, accessible downstream as $vars.<nodeName>.output:
return {
message: "Processed",
count: items.length
};
return {
message: "Processed",
count: items.length
};
输入和输出
输入
The Script node can access any upstream variable via $vars. It does not have a typed input schema — anything in $vars is available.
输出
On success — $vars.<nodeName>.output:
The return value of the script. Shape depends on what the script returns.
On failure (when an error handle is connected) — $vars.<nodeName>.error:
{
"code": "string",
"message": "string",
"detail": "string",
"category": "string",
"status": 0
}
{
"code": "string",
"message": "string",
"detail": "string",
"category": "string",
"status": 0
}
Generate scripts with AI
The magic wand icon above the script editor accepts a plain-language description of what you want and generates the JavaScript for you. This is useful for accessing an upstream node's output or writing a quick transformation without looking up the exact $vars syntax.
示例
Example 1 — Set a process variable
// Set a variable that downstream nodes can reference
return {
orderTotal: $vars.httpRequest1.output.body.price * $vars.httpRequest1.output.body.quantity,
currency: "USD"
};
// Set a variable that downstream nodes can reference
return {
orderTotal: $vars.httpRequest1.output.body.price * $vars.httpRequest1.output.body.quantity,
currency: "USD"
};
Downstream nodes access the values as $vars.script1.output.orderTotal and $vars.script1.output.currency.
Example 2 — Process an HTTP response
const data = $vars.httpRequest1.output.body;
return {
title: data.title,
userId: data.userId
};
const data = $vars.httpRequest1.output.body;
return {
title: data.title,
userId: data.userId
};
Example 3 — Conditional logic
const status = $vars.httpRequest1.output.statusCode;
if (status === 200) {
return { success: true, data: $vars.httpRequest1.output.body };
} else {
return { success: false, statusCode: status };
}
const status = $vars.httpRequest1.output.statusCode;
if (status === 200) {
return { success: true, data: $vars.httpRequest1.output.body };
} else {
return { success: false, statusCode: status };
}
Example 4 — Transform an array
const items = $vars.fetchItems1.output.body;
return {
count: items.length,
names: items.map(item => item.name)
};
const items = $vars.fetchItems1.output.body;
return {
count: items.length,
names: items.map(item => item.name)
};
When to use this vs Data Transform
| Use Script when... | Use Data Transform when... |
|---|---|
| You need full JavaScript logic — loops, conditionals, string manipulation | You need a simple field mapping or no-code transformation |
| You want to compute something from upstream node output | You want a visual mapper without writing code |
| The transformation is complex or stateful | The transformation is a straightforward reshape |
相关页面
- Variables and data flow —
$vars, expression syntax, variable scoping - HTTP Request node — typical upstream data source
- Decision node — branch based on Script output
- 操作
- Configuration reference
- The JavaScript environment
- Accessing upstream node output
- 返回值
- 输入和输出
- 输入
- 输出
- Generate scripts with AI
- 示例
- Example 1 — Set a process variable
- Example 2 — Process an HTTP response
- Example 3 — Conditional logic
- Example 4 — Transform an array
- When to use this vs Data Transform
- 相关页面