Flow Logic

The wfa.flowLogic namespace provides control flow operators for branching, looping, and flow control within Flow and Subflow bodies.

Usage Pattern

All flow logic constructs follow this invocation shape:

wfa.flowLogic.<construct>(
  { $id: Now.ID['logic_id'], ...params },
  callback?
)

---

wfa.flowLogic.if

Evaluates a condition and executes the callback if true.

Signature

wfa.flowLogic.if(
  params: {
    $id: string,
    condition: string,
    label?: string,
    annotation?: string
  },
  body: () => void
)

Parameters

Parameter	Type	Required	Default	Description
$id	string	Yes	-	Unique identifier (Now.ID['value'])
condition	string	Yes	-	Encoded query expression to evaluate
label	string	No	-	Display label for this branch
annotation	string	No	-	Description/comment

---

wfa.flowLogic.elseIf

Evaluates a condition if previous conditions were false. Must follow if or elseIf.

Signature

wfa.flowLogic.elseIf(
  params: {
    $id: string,
    condition: string,
    label?: string,
    annotation?: string
  },
  body: () => void
)

Parameters

Parameter	Type	Required	Default	Description
$id	string	Yes	-	Unique identifier (Now.ID['value'])
condition	string	Yes	-	Encoded query expression to evaluate
label	string	No	-	Display label for this branch
annotation	string	No	-	Description/comment

---

wfa.flowLogic.else

Executes callback if all previous conditions were false. Must follow if or elseIf.

Signature

wfa.flowLogic.else(
  params: {
    $id: string,
    annotation?: string
  },
  body: () => void
)

Parameters

Parameter	Type	Required	Default	Description
$id	string	Yes	-	Unique identifier (Now.ID['value'])
annotation	string	No	-	Description/comment

---

wfa.flowLogic.forEach

Iterates over an array, executing the callback for each item.

Signature

wfa.flowLogic.forEach<TArray>(
  items: TArray,
  config: {
    $id: string,
    annotation?: string
  },
  body?: (item: ExtractArrayElement<TArray>) => void
)

Parameters

Parameter	Type	Required	Default	Description
items	TArray	Yes	-	Array to iterate (use data pill with array type)
$id	string	Yes	-	Unique identifier (Now.ID['value'])
annotation	string	No	-	Description/comment
body	function	No	-	Callback receiving each item

Supported Data Pill Types

• 'array.object' — For lookUpRecords results and object arrays
• 'array.string' — For string arrays (no item parameter)

---

wfa.flowLogic.exitLoop

Immediately exits the enclosing forEach loop.

Signature

wfa.flowLogic.exitLoop(
  params: {
    $id: string,
    annotation?: string
  }
)

Parameters

Parameter	Type	Required	Default	Description
$id	string	Yes	-	Unique identifier (Now.ID['value'])
annotation	string	No	-	Description/comment

---

wfa.flowLogic.skipIteration

Skips the current iteration and continues with the next item.

Signature

wfa.flowLogic.skipIteration(
  params: {
    $id: string,
    annotation?: string
  }
)

Parameters

Parameter	Type	Required	Default	Description
$id	string	Yes	-	Unique identifier (Now.ID['value'])
annotation	string	No	-	Description/comment

---

wfa.flowLogic.endFlow

Immediately terminates flow execution.

Signature

wfa.flowLogic.endFlow(
  params: {
    $id: string,
    annotation?: string
  }
)

Parameters

Parameter	Type	Required	Default	Description
$id	string	Yes	-	Unique identifier (Now.ID['value'])
annotation	string	No	-	Description/comment

---

wfa.flowLogic.doInParallel

Executes multiple code blocks in parallel within a flow.

Signature

wfa.flowLogic.doInParallel(
  params: {
    $id: string,
    annotation?: string
  },
  ...blocks: (() => void)[]
)

Parameters

Parameter	Type	Required	Default	Description
$id	string	Yes	-	Unique identifier (Now.ID['value'])
annotation	string	No	-	Description/comment
blocks	() => void	Yes	-	One or more arrow functions to execute in parallel

Important Constraints

• No nesting — doInParallel cannot be used inside another doInParallel block
• Minimum 1 block — At least one parallel block is required
• Each block is an arrow function: () => { ... }
• Datapill scope limitation — Action output datapills captured inside a doInParallel block are not accessible outside it. To use an action output after the block, assign it to a flow variable inside the block using wfa.flowLogic.setFlowVariables, then reference the flow variable outside.

---

wfa.flowLogic.tryCatch

Creates a try-catch block for error handling in flows.

Signature

wfa.flowLogic.tryCatch(
  params: {
    $id: string,
    annotation?: string
  },
  handlers: {
    try: () => void,
    catch: () => void
  }
)

Parameters

Parameter	Type	Required	Default	Description
$id	string	Yes	-	Unique identifier (Now.ID['value'])
annotation	string	No	-	Description/comment
handlers	object	Yes	-	Object with try and catch arrow functions

Handlers Object

Property	Type	Required	Description
try	() => void	Yes	Arrow function containing code to attempt
catch	() => void	Yes	Arrow function to execute if try block fails

Important Notes

• Both try and catch must be arrow functions
• tryCatch blocks can be nested
• The catch block executes only if an error occurs in the try block
• Datapill scope limitation — Action output datapills captured inside a tryCatch block are not accessible outside it. To use an action output after the block, assign it to a flow variable inside the block using wfa.flowLogic.setFlowVariables, then reference the flow variable outside.

---

wfa.flowLogic.appendToFlowVariables

Appends element(s) to array-typed flow variables.

Signature

wfa.flowLogic.appendToFlowVariables<V>(
  params: {
    $id: string,
    annotation?: string
  },
  variables: V,
  values: Partial<{
    [K in keyof V]: V[K] extends Array<infer E> 
      ? E | E[] | unknown[] | string 
      : never
  }>
)

Parameters

Parameter	Type	Required	Default	Description
$id	string	Yes	-	Unique identifier (Now.ID['value'])
annotation	string	No	-	Description/comment
variables	V	Yes	-	Flow variables schema (pass params.flowVariables)
values	object	Yes	-	Key/value pairs where keys are array variable names

Value Types

For each array variable, you can append:

• Single element — { arrayVar: singleElement }
• Array of elements — { arrayVar: [elem1, elem2, elem3] }
• Data pill — { arrayVar: wfa.dataPill(...) }
• Template string — { arrayVar: 'template expression' }

Important Constraints

• Array.Object only — Only supports FlowArray({ elementType: FlowObject(...) }) variables
• Array elements must be objects or datapill expressions — When appending an array literal, each element must be an object or a datapill expression
• Compile-time safety — TypeScript enforces that target variables are arrays

---

wfa.flowLogic.setFlowVariables

Assigns values to flow-scoped variables declared in the Flow or Subflow config flowVariables property. This is a type-only helper — it is erased at runtime and only influences the TypeScript type-checker.

Signature

wfa.flowLogic.setFlowVariables(
  definition: { $id: string, annotation?: string },
  variables: FlowSchemaType<S>,
  values: { [K in keyof FlowSchemaType<S>]?: FlowSchemaType<S>[K] | string }
)

Parameters

Parameter	Type	Required	Description
$id	string	Yes	Unique identifier (Now.ID['value'])
annotation	string	No	Description/comment
variables	FlowSchemaType<S>	Yes	Flow variables schema — always pass params.flowVariables
values	Partial record	Yes	Key/value pairs of variables to set. Omitted keys are unchanged.

Value Types

For each variable entry in values, you can supply:

• Typed literal — { myVar: 'hello' }, { count: 42 }
• Data pill — { myVar: wfa.dataPill(params.trigger.current.short_description, 'string') }
• Template string — { myVar: 'template expression' }

null and undefined are not valid — omit the key instead of setting it to null.

Important Notes

• Always pass params.flowVariables as the variables argument — never construct a custom object.
• Only the keys listed in values are updated; other flow variables retain their current values.
• Flow variables are scoped to the current flow or subflow execution — they are not visible to called subflows.

---

Condition Syntax Reference

Flow logic conditions use ServiceNow encoded query format.

Comparison Operators

Operator	Description	Example
=	Equals	priority=1
!=	Not equals	state!=6
<	Less than	priority<3
<=	Less or equal	priority<=2
>	Greater than	priority>3
>=	Greater or equal	priority>=2

Empty/Not Empty Operators

Operator	Description	Example
ISEMPTY	Field is empty	assigned_toISEMPTY
ISNOTEMPTY	Field has value	assignment_groupISNOTEMPTY

List Operators

Operator	Description	Example
IN	In list	stateIN1,2,3
NOT IN	Not in list	stateNOT IN6,7

String Operators

Operator	Description	Example
STARTSWITH	Starts with	numberSTARTSWITHINC
ENDSWITH	Ends with	emailENDSWITH@company.com
CONTAINS	Contains	short_descriptionCONTAINSfailed

Logical Operators

Operator	Description	Example
^ or ^AND	Logical AND	priority=1^active=true
^OR	Logical OR	priority=1^ORpriority=2
^NQ	New query (OR group)	priority=1^NQstate=2

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For usage patterns, examples, best practices, and end-to-end flow logic examples, see the Flow Logic Guide.