branch()

Creates a binary conditional branch in a pipeline. The step itself outputs matching values; the .fail branch is accessible as "stepName.fail".

Signature

function branch<T>(
	dep: string,
	predicate: (value: T) => boolean,
	opts?: { name?: string },
): BranchStepDef<T>

Parameters

Parameter	Type	Description
dep	string	Name of the upstream step to branch on.
predicate	(value: T) => boolean	Function that returns true for matching (pass) values.
opts	{ name?: string }	Optional configuration.

Returns

BranchStepDef<T> — step definition for pipeline(). The matching branch is the step itself; "stepName.fail" is auto-registered by pipeline().

Basic Usage

import { pipeline, step, task, branch, fromTrigger } from 'callbag-recharge/orchestrate';

const wf = pipeline({
    input:    step(fromTrigger<number>()),
    check:    branch("input", v => v > 0),
    positive: task(["check"], async (v) => `good: ${v}`),
    negative: task(["check.fail"], async (v) => `bad: ${v}`),
  });

Options / Behavior Details

• Diamond-safe: Both outputs use route() internally, with suppression signaling on the inactive branch to prevent blocking downstream diamond joins.