3.7.14. Multiple Step Usage in Workflows
In this chapter, you'll learn how to use a step multiple times in a workflow.
Problem Reusing a Step in a Workflow#
In some cases, you may need to use a step multiple times in the same workflow.
The most common example is using the useQueryGraphStep multiple times in a workflow to retrieve multiple unrelated data, such as customers and products.
Steps must have a unique ID, which you pass as the first parameter of the createStep function.
So, when a step is used multiple times in a workflow, it's registered multiple times in the workflow with the same ID, which causes an error.
1const helloWorkflow = createWorkflow(2 "hello",3 () => {4 const { data: products } = useQueryGraphStep({5 entity: "product",6 fields: ["id"],7 })8 9 // ERROR OCCURS HERE: A STEP HAS THE SAME ID AS ANOTHER IN THE WORKFLOW10 const { data: customers } = useQueryGraphStep({11 entity: "customer",12 fields: ["id"],13 })14 }15)
The next section explains how to fix this issue to use the same step multiple times in a workflow.
How to Use a Step Multiple Times in a Workflow?#
When you execute a step in a workflow, you can chain a config method to it to change the step's config.
Use the config method to change a step's ID for a single execution.
For example, this is the correct way to write the example above:
1const helloWorkflow = createWorkflow(2 "hello",3 () => {4 const { data: products } = useQueryGraphStep({5 entity: "product",6 fields: ["id"],7 })8 9 // ✓ No error occurs, the step has a different ID.10 const { data: customers } = useQueryGraphStep({11 entity: "customer",12 fields: ["id"],13 }).config({ name: "fetch-customers" })14 }15)
The config method accepts an object with a name property. Its value is the new ID for the step to use for this execution only.
The first useQueryGraphStep usage has the ID use-query-graph, and the second useQueryGraphStep usage has the ID fetch-customers.
