How to define Workflow parameters in TypeScript

You can define and pass parameters in your Workflow. In this example, you define your arguments in your client.ts file and pass those parameters to workflow.ts through your Workflow function.

Start a Workflow with the parameters that are in the client.ts file. In this example we set the name parameter to Temporal and born to 2019. Then set the Task Queue and Workflow Id.

client.ts

import { example } from './workflows';

...
await client.start(example, {
  args: [{ name: 'Temporal', born: 2019 }],
  taskQueue: 'your-queue',
  workflowId: 'business-meaningful-id',
});

In workflows.ts define the type of the parameter that the Workflow function takes in. The interface ExampleParam is a name we can now use to describe the requirement in the previous example. It still represents having the two properties called name and born that is of the type string. Then define a function that takes in a parameter of the type ExampleParam and return a Promise<string>. The Promise object represents the eventual completion, or failure, of await client.start() and its resulting value.

TypeScript

interface ExampleParam {
  name: string;
  born: number;
}
export async function example({ name, born }: ExampleParam): Promise<string> {
  return `Hello ${name}, you were born in ${born}.`;
}

JavaScript

export async function example({ name, born }) {
  return `Hello ${name}, you were born in ${born}.`;
}