Workflow.if() (experimental)

The .if() method creates a conditional branch in the workflow, allowing steps to execute only when a specified condition is true. This enables dynamic workflow paths based on the results of previous steps.

Usage

workflow
  .step(startStep)
  .if(async ({ context }) => {
    const value = context.getStepResult<{ value: number }>('start')?.value;
    return value < 10; // If true, execute the "if" branch
  })
  .then(ifBranchStep)
  .else()
  .then(elseBranchStep)
  .commit();

Parameters

condition:

Function | ReferenceCondition

A function or reference condition that determines whether to execute the 'if' branch

Condition Types

Function Condition

You can use a function that returns a boolean:

workflow
  .step(startStep)
  .if(async ({ context }) => {
    const result = context.getStepResult<{ status: string }>('start');
    return result?.status === 'success'; // Execute "if" branch when status is "success"
  })
  .then(successStep)
  .else()
  .then(failureStep);

Reference Condition

You can use a reference-based condition with comparison operators:

workflow
  .step(startStep)
  .if({
    ref: { step: startStep, path: 'value' },
    query: { $lt: 10 }, // Execute "if" branch when value is less than 10
  })
  .then(ifBranchStep)
  .else()
  .then(elseBranchStep);

Returns

workflow:

Workflow

The workflow instance for method chaining

Error Handling

The if method requires a previous step to be defined. If you try to use it without a preceding step, an error will be thrown:

try {
  // This will throw an error
  workflow
    .if(async ({ context }) => true)
    .then(someStep)
    .commit();
} catch (error) {
  console.error(error); // "Condition requires a step to be executed after"
}

Reference: Workflow.else() | Conditional Branching | Mastra Docs Memory Class