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.waitForADuration

Pauses flow execution for a specified duration. Supports explicit durations, relative durations, and percentage-based durations.

Signature

wfa.flowLogic.waitForADuration(
  params: WaitForADurationParams
): WaitForADurationOutputs

WaitForADurationParams is $id plus one of three discriminated variants determined by durationType:

Explicit Duration (durationType: 'explicit_duration')

Parameter	Type	Required	Default	Description
$id	string	Yes	-	Unique identifier (Now.ID['value'])
durationType	'explicit_duration'	Yes	-	Duration variant selector
duration	Duration	No	-	The duration to wait. When omitted, platform uses zero duration
schedule	Record<'cmn_schedule'> | string	No	-	Optional schedule for business-hours calculation
annotation	string	No	-	Description/comment
uuid	string	No	-	UUID for referencing this instance's outputs as datapills

Relative Duration (durationType: 'relative_duration')

Parameter	Type	Required	Default	Description
$id	string	Yes	-	Unique identifier (Now.ID['value'])
durationType	'relative_duration'	Yes	-	Duration variant selector
duration	Duration	Yes	-	The duration to offset
relativeOperator	'before' | 'after'	Yes	-	Whether to wait before or after the reference datetime
relativeDatetime	string	Yes	-	Reference datetime for the relative calculation
schedule	Record<'cmn_schedule'> | string	No	-	Optional schedule for business-hours calculation
annotation	string	No	-	Description/comment
uuid	string	No	-	UUID for referencing this instance's outputs as datapills

Percentage Duration (durationType: 'percentage_duration')

Parameter	Type	Required	Default	Description
$id	string	Yes	-	Unique identifier (Now.ID['value'])
durationType	'percentage_duration'	Yes	-	Duration variant selector
percentage	number	Yes	-	Percentage value for percentage-based duration
percentageDatetime	string	Yes	-	Reference datetime for percentage-based calculation
schedule	Record<'cmn_schedule'> | string	No	-	Optional schedule for business-hours calculation
annotation	string	No	-	Description/comment
uuid	string	No	-	UUID for referencing this instance's outputs as datapills

Return Value

Field	Type	Description
total_duration	Duration	The total duration that was waited
scheduled_end_date_time	datetime	The scheduled end date/time when the wait completed

---

wfa.flowLogic.assignSubflowOutputs

Assigns the subflow's output values from within the subflow body, mapping declared output names to values, datapill references, or template literals. This is the recommended way to set subflow outputs based on step results. Type-only helper — erased at runtime.

Signature

wfa.flowLogic.assignSubflowOutputs(
  definition: { $id: string, annotation?: string },
  variables: TOutputs,         // always pass params.outputs
  values: Partial<TOutputs>    // fields to assign; omitted fields are undefined
)

Parameters

Parameter	Type	Required	Description
$id	string	Yes	Unique identifier for this assignment node
annotation	string	No	Description/comment
variables	TOutputs	Yes	Always pass params.outputs -- do not construct a custom object
values	Partial<TOutputs>	Yes	Key/value pairs to assign. Values may be literals or data pills

⚠️ Type-only helper. This call is erased at runtime; it exists for compile-time type safety.

---

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.