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

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.

src/mastra/workflows/test-workflow.ts


const step1 = createStep({...});
const step2 = createStep({...});
 
export const testWorkflow = createWorkflow({
  id: "test-workflow",
  description: 'Test workflow',
  inputSchema: z.object({
    input: z.number()
  }),
  outputSchema: z.object({
    output: z.string()
  })
})
  .then(step1)
  .map(({ inputData }) => {
    const { value } = inputData;
    return {
      output: `${value}`
    };
  })
  .then(step2)
  .commit();

inputData

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


  .map(({ inputData }) => {
    const { value} = inputData;
    ...
  })

getStepResult

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


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

getInitData

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


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

Renaming Outputs

Step Outputs

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

Workflow Outputs

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


export const testWorkflow = createWorkflow({
  id: "test-workflow",
  description: 'Test workflow',
  inputSchema: z.object({
    input: z.string()
  }),
  outputSchema: z.object({
    output: z.string()
  })
});
 
testWorkflow
  .then(cityCoordinatesStep)
  .map({
    details: mapVariable({
      initData: testWorkflow,
      path: "value"
    })
  })