#Expression examples

Ready-made expressions for the common cases — conditions, defaults, sums, picked fields, dates, text, request bodies, multi-instance results, the initiator and files.

The ids below — StartEvent_order, Activity_fetch — stand for the element ids in your process. Pick yours with + in the field.

flowchart LR
  S["StartEvent_order<br/>orderId, amount, orderDate"] --> F["Activity_fetch<br/>customer, items[]"]
  F --> G{{"Gateway"}}
  G --> R["Activity_review<br/>(only on some paths)"]
  G --> N["Next step:<br/>the examples read these"]
  R --> N

#Conditions on a gateway

Goal	Expression
Amount over a limit	`StartEvent_order.amount > 1000`
Both must hold	`StartEvent_order.amount > 1000 && Activity_fetch.customer.isNew`
A list is not empty	`(Activity_fetch.items \|\| []).length > 0`
A text is one of several	`["DE", "AT", "CH"].includes(Activity_fetch.customer.country)`

#A default when something may be missing

Goal	Expression
A field that may be empty	`Activity_fetch.customer.phone ?? "none"`
A step that ran only on some paths	`typeof Activity_review === "undefined" ? "not reviewed" : Activity_review.comment`

Activity_review?.comment is not enough when the step never ran — see Write an expression.

#Work with lists

Goal	Expression
Sum	`Activity_fetch.items.reduce((sum, i) => sum + i.price * i.qty, 0)`
Only some items	`Activity_fetch.items.filter(i => i.inStock)`
One field of every item	`Activity_fetch.items.map(i => i.sku)`
The first match	`Activity_fetch.items.find(i => i.sku === "A-100")`
Options for a select, in Option data	`Activity_fetch.items.map(i => ({ value: i.sku, label: i.name }))`

#Dates and text

Goal	Expression
Today, as `2026-09-30`	`new Date().toISOString().slice(0, 10)`
A date as `30.09.2026`	`(() => { const d = new Date(StartEvent_order.orderDate); return String(d.getUTCDate()).padStart(2, "0") + "." + String(d.getUTCMonth() + 1).padStart(2, "0") + "." + d.getUTCFullYear(); })()`
Text with values	`Order ${StartEvent_order.orderId} for ${Activity_fetch.customer.name}`
Text depending on a value	`StartEvent_order.amount > 1000 ? "needs approval" : "approved"`

⚠️ Formatting for a language — toLocaleDateString("de-DE") — is accepted, but the language is ignored. Build the text yourself, as above.

#A request body

{
  customer: { id: Activity_fetch.customer.id, email: Activity_fetch.customer.email },
  total: Activity_fetch.items.reduce((sum, i) => sum + i.price * i.qty, 0),
  note: `Order ${StartEvent_order.orderId}`
}

Write it with ƒ on the Request body — see Fixed values, variables and expressions in a field.

#Multi-instance

Goal	Expression
Inside the step: the current item	`__loop.item.email`
Inside the step: its position	`__loop.index`
After the step: every result	`Activity_notify.map(r => r.status)`
After the step: were all approved?	`Activity_approve.every(r => r.approved)`
After the step: the first result	`Activity_notify[0].status`

With First completion or Number of completions, the list after the step holds only the runs that finished — see Run a step once per item.

#The initiator

Goal	Expression
Their email	`__INITIATOR.email`
Their full name	`${__INITIATOR.firstName} ${__INITIATOR.lastName}`

⚠️ Empty when nobody started the process by hand — for example a webhook start.

#Files

Goal	Expression
Send a file's content in a request body	`{ document: Activity_upload.invoice.file }`
Attach a file to an email	`Activity_upload.invoice` in Attachments
A file's name	`Activity_upload.invoice.fileName`

.file loads the file itself only in a request body, in the email fields and in attachments; elsewhere it is an ordinary field name.

#A message filter

Goal	Expression
Only one kind of event	`payload.event.type === "invoice.paid"`
Ignore messages from bots	`!payload.event.bot_id`
By a header	`headers["x-source"] === "shop"`

A filter reads only the request — see Where expressions are used.