Input Data Mapping

Input data mapping allows explicit mapping of values for the inputs of the next step. These values can come from a number of sources:

• The outputs of a previous step
• The runtime context
• A constant value
• The initial input of the workflow

Mapping with .map()

In this example the output from step1 is transformed to match the inputSchema required for the step2. The value from step1 is available using the inputData parameter of the .map function.

const step1 = createStep({...});
const step2 = createStep({...});
 
export const testWorkflow = createWorkflow({...})
  .then(step1)
  .map(async ({ inputData }) => {
    const { value } = inputData;
    return {
      output: `new ${value}`
    };
  })
  .then(step2)
  .commit();

Using inputData

Use inputData to access the full output of the previous step:

  .then(step1)
  .map(({ inputData }) => {
    console.log(inputData);
  })

Using getStepResult()

Use getStepResult to access the full output of a specific step by referencing the step’s instance:

  .then(step1)
  .map(async ({ getStepResult }) => {
    console.log(getStepResult(step1));
  })

Using getInitData()

Use getInitData to access the initial input data provided to the workflow:

  .then(step1)
  .map(async ({ getInitData }) => {
      console.log(getInitData());
  })

Using mapVariable()

To use mapVariable import the necessary function from the workflows module:

import { mapVariable } from "@mastra/core/workflows";

Renaming step with mapVariable()

You can rename step outputs using the object syntax in .map(). In the example below, the value output from step1 is renamed to details:

  .then(step1)
  .map({
    details: mapVariable({
      step: step,
      path: "value"
    })
  })

Renaming workflows with mapVariable()

You can rename workflow outputs by using referential composition. This involves passing the workflow instance as the initData.

export const testWorkflow = createWorkflow({...});
 
testWorkflow
  .then(step1)
  .map({
    details: mapVariable({
      initData: testWorkflow,
      path: "value"
    })
  })