JavaScript in World of Workflows

The following JavaScript expressions are supported:

Variables

Workflow Variables

Any workflow variable can be accessed directly as if they were a global variable.

For example, if the Set Variable activity sets a variable called FirstName to ‘Luke’, it can be accessed as follows:

return `Hello ${FirstName}`

or it can be accessed by

 return 'Hello '+getVariable("FirstName")

Value returned will be:

Hello Luke

This also works when setting variables using the setVariable() function. Because ultimately, both the SetVariable activity and setVariable() function use the same API under the cover to set a workflow variable.

JavaScript and Liquid are case sensitive.

Activity Output

A activity might provide some output which can then be accessed from any other activity using workflow expressions. For example, to access an activity’s output property called OUTPUT using a JavaScript expression, you can do so by specifying activities, then the activity name followed by .Output().

You must put () at the end of a method, and not at the end of a property.

Methods and properties

For example, if you have an activity named MyActivity, you can access its output as follows:

activities.MyActivity.Output()

Note that the Intellisense prompts you to include () when you see (method) in the description. For example

See the difference when Intellisense shows a property is needed: In this case you do not include the () at the end:

If the output is an object, you can access its properties too. For instance, the HTTP Endpoint activity returns the HTTP request as its output which is of type HTTPREQUESTMODEL. When you name this activity MyHttpEndpoint, you can access the HTTP request Body like this:

activities.MyHttpEndpoint.Output().Body

If you happened to post a JSON document to your HTTP endpoint that looks like this:

{
  "MyDocument": {
    "Title": "About Elsa Workflows"
  }
}

Then you can access the Title field like this:

activities.MyHttpEndpoint.Output().Body.MyDocument.Title

If your activity is a direct child of an HTTP Endpoint activity, you can access its output directly via the input variable, which will be an instance of HTTPREQUESTMODEL.

input

Contains the input value that was received as output from the previously executed activity, if any.

input: object?

workflowInstanceId

Contains the workflow instance ID of the currently executing workflow.

workflowInstanceId: string

workflowDefinitionId

Contains the workflow definition ID of the currently executing workflow.

workflowDefinitionId: string

workflowDefinitionVersion

Contains the workflow definition version of the currently executing workflow.

workflowDefinitionVersion: number

correlationId

Contains the correlation ID of the currently executing workflow.

correlationId: string?

currentCulture

Contains the current culture.

currentCulture: CultureInfo

Currently, this value is always set to CultureInfo.InvariantCulture.

workflowContext

Contains the workflow context (if any) of the currently executing workflow.

workflowContext: object?

Common Functions

guid

Generates a new GUID value and returns its string representation.

guid(): string

This function is a thin wrapper around the following .NET code: Guid.NewGuid().ToString().

parseGuid

Parses a string into a GUID value.

parseGuid(value: string): Guid

This function is a thin wrapper around the following .NET code: Guid.Parse(value).

setVariable

Sets a workflow variable to the specified value.

setVariable(name: string, value: object): void

This function is a thin wrapper around the following .NET code: activityContext.SetVariable(name, value).

getVariable

Returns a workflow variable with the specified name.

getVariable(name: string): object

Instead of using getVariable(name: string), you can access workflow variables directly as described above in the Workflow Variables section.

This function is a thin wrapper around the following .NET code: activityContext.GetVariable(name).

getConfig

Provides access to a .NET configuration value.

getConfig(name: string): string

As an example, let’s say you have the following JSON in appsettings.json:

{
  "Elsa": {
    "Smtp": {
      "Host": "localhost",
      "Port": 2525
    }
  }
}

You can access the configured Port value using the following expression:

getConfig("Elsa:Smtp:Port") // returns '2525'

This function is a thin wrapper around the following .NET code: configuration.GetSection(name).Value where configuration is an instance of IConfiguration.

isNullOrWhiteSpace

Returns true if the specified string is null, empty or consists of white space only, false otherwise.

isNullOrWhiteSpace(value: string): boolean

This function is a thin wrapper around the following .NET code: string.IsNullOrWhiteSpace(value).

isNullOrEmpty

Returns true if the specified string is null or empty, false otherwise.

isNullOrEmpty(value: string): boolean

This function is a thin wrapper around the following .NET code: string.IsNullOrEmpty(value).

 

Workflow Functions

getWorkflowDefinitionIdByName

Returns the ID of the specified workflow by name. This is useful when for instance you are using the RUNWORKFLOW activity, which requires the ID of the workflow definition to run.

getWorkflowDefinitionIdByName(name: string): string?

For example: set the Workflow Definition in a RUNWORKFLOW activity to MyWorkflow : getWorkflowDefinitionIdByName(‘MyWorkflow’)

getWorkflowDefinitionIdByTag

Returns the ID of the specified workflow by tag. This is useful when for instance you are using the RUNWORKFLOW activity, which requires the ID of the workflow definition to run.

getWorkflowDefinitionIdByTag(tag: string): string?

HTTP Functions

queryString

Returns the value of the specified query string parameter.

queryString(name: string): string

absoluteUrl

Converts the specified relative path into a fully-qualified absolute URL.

absoluteUrl(path: string): string

signalUrl

Generates a fully-qualified absolute signal URL that will trigger the workflow instance from which this function is invoked.

signalUrl(signal: string): string

Date/Time Functions

instantFromDateTimeUtc

Returns a new Instant object from the specified DateTime value.

Make sure that the DateTime value’s Kind property is DateTimeKind.Utc.

currentInstant

Returns the current date/time value in the form of a NodaTime’s Instant object.

currentInstant(): Instant

currentYear

Returns the current year.

currentYear(): number

startOfMonth

Returns the start of the month of the specified instant. If no instant is specified, the current instant is used.

startOfMonth(instant: Instant?): LocalDate;

endOfMonth(instant: Instant?)

Returns the end of the month of the specified instant. If no instant is specified, the current instant is used.

endOfMonth(instant: Instant?): LocalDate;

startOfPreviousMonth

Returns the start of the previous month of the specified instant. If no instant is specified, the current instant is used.

startOfPreviousMonth(instant: Instant?): LocalDate;

plus

Adds the specified Duration to the specified Instant and returns the result.

plus(instant: Instant, duration: Duration): Instant

minus

Subtracts the specified Duration from the specified Instant and returns the result.

minus(instant: Instant, duration: Duration): Instant

durationFromDays

Returns a duration constructed from the specified number of days.

durationFromDays(days: number): Duration

formatInstant

Formats the specified Instant using the specified format string and CultureInfo. If no culture info is provided, CultureInfo.InvariantCulture is used.

formatInstant(instant: Instant, format: string, cultureInfo: CultureInfo?): string

localDateFromInstant

Returns the LocalDate portion of the specified Instant.

localDateFromInstant(instant: Instant): LocalDate

instantFromLocalDate

Creates an Instant from the specified LocalDate value (start of date).

instantFromLocalDate(localDate: LocalDate): Instant

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