- はじめに
- 基本情報
- BPMN を使用したプロセス モデリング
- ケース管理を使用したプロセス モデリング
- Process modeling with Flow
- 基本情報
- 中心となる概念
- Node reference
- Build guides
- ベスト プラクティス
- 参照
- プロセスの実装
- プロセスの操作
- プロセスの監視
- プロセスの最適化
- 参考情報
Maestro ユーザー ガイド
機能
Runs JavaScript code and passes the return value to downstream nodes.
Configuration reference
| フィールド | Required | 既定 (Default) | 説明 |
|---|---|---|---|
| スクリプト | はい | なし | 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;
戻り値
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
};
入力と出力
入力
The Script node can access any upstream variable via $vars. It does not have a typed input schema — anything in $vars is available.
出力
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.
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 |
関連ページ
- Variables and data flow —
$vars, expression syntax, variable scoping - HTTP Request node — typical upstream data source
- Decision node — branch based on Script output
- 機能
- Configuration reference
- The JavaScript environment
- Accessing upstream node output
- 戻り値
- 入力と出力
- 入力
- 出力
- Generate scripts with AI
- 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
- 関連ページ