Router

Basic usage​

Router checks its conditions in order. The first branch that evaluates to true is taken, and if none match, execution follows the Else branch.

Configuration​

The node's property panel:

×

Name​

The name shown on the canvas, used to identify this processor within the workflow.

Description​

Explains what this processor is for, making the workflow easier to read.

Properties​

You can add as many condition branches as you need. Each carries a name and a condition.

Value types​

• Literal: enter true or false directly
• Expression: evaluate the condition with a JavaScript expression
• Template: evaluate the condition with template syntax

For how values are resolved, see Expression introduction — resolving values.

In the Workflow CRD​

Each branch is one config, named case-1, case-2 and so on, whose value is that branch's condition. The branch name is also the relationship name, so adding a case adds both a setting and an outgoing edge.

- name: proc-route
  type: router
  labels:
    display_name: Is this a return enquiry
  configs:
    - name: case-1
      expression: |-
        (() => {
          return /return|refund/.test(prevMessage);
        })()
    - name: case-2
      expression: |-
        (() => {
          return /shipping|delivery/.test(prevMessage);
        })()

The default relationships are case-1 and else. else takes no condition and is followed when no case holds.

Relationships​

Dynamic branches​

A connection point is created for each condition configured in Properties. When a condition evaluates to true, the workflow continues from that branch.

Else​

When no dynamic condition matches, the workflow continues from this connection point, which acts as the default path.

A worked example​

Decide whether to raise a restock notice based on a stock query. Press + under Properties to add one case:

A branch called need_restock appears on the node, which together with the built-in Else gives it two exits. The condition has to return a boolean.

How the conditions are evaluated​

Router walks the cases in the order they were added. The first one that holds wins and evaluation stops; the cases after it are never looked at. Only if none hold does the flow take Else.

A value is not simply truthy or falsy:

• A boolean is used as-is.
• A string is parsed with strconv.ParseBool, so true, false, 1, 0, t, f work. A string it cannot parse goes to Failure, it is not treated as false.
• Anything that is neither a boolean nor a string -- an object, a number, null -- goes to Failure.

This catches people out: a condition whose expression returns a non-boolean does not quietly fall through to Else, it fails the node.