This tutorial explains three techniques for creating triggers:
  • Polling: Periodically call endpoints to check for changes.
  • Webhooks: Listen to user events through a single URL.
  • App Webhooks (Subscriptions): Use a developer app (using OAuth2) to receive all authorized user events at a single URL (Not Supported).
to create new trigger run following command, 
npm run cli triggers create
  1. Piece Folder Name: This is the name associated with the folder where the trigger resides. It helps organize and categorize triggers within the piece.
  2. Trigger Display Name: The name users see in the interface, conveying the trigger’s purpose clearly.
  3. Trigger Description: A brief, informative text in the UI, guiding users about the trigger’s function and purpose.
  4. Trigger Technique: Specifies the trigger type - either polling or webhook.

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Trigger Structure

export const createNewIssue = createTrigger({
    auth: PieceAuth | undefined
    name: string, // Unique name across the piece.
    displayName: string, // Display name on the interface.
	description: string, // Description for the action
    triggerType: POLLING | WEBHOOK,

    props: {}; // Required properties from the user.
    // Run when the user enable or publish the flow.

	onEnable: (ctx) => {};
    // Run when the user disable the flow or
    // the old flow is deleted after new one is published.
	onDisable: (ctx) => {};

    // Trigger implementation, It takes context as parameter.
    // should returns an array of payload, each payload considered
    // a separate flow run.
    run: async run(ctx): unknown[] => {}
})
It’s important to note that the run method returns an array. The reason for this is that a single polling can contain multiple triggers, so each item in the array will trigger the flow to run.

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Context Object

The Context object contains multiple helpful pieces of information and tools that can be useful while developing. 
// Store: A simple, lightweight key-value store that is helpful when you are developing triggers that persist between runs, used to store information like the last polling date.
await context.store.put('_lastFetchedDate', new Date());
const lastFetchedData = await context.store.get('_lastFetchedDate', new Date());

// Webhook URL: A unique, auto-generated URL that will trigger the flow. Useful when you need to develop a trigger based on webhooks.
context.webhookUrl;

// Payload: Contains information about the HTTP request sent by the third party. It has three properties: status, headers, and body.
context.payload;

// PropsValue: Contains the information filled by the user in defined properties.
context.propsValue;
App Webhooks (Not Supported) Certain services, such as Slack and Square, only support webhooks at the developer app level. This means that all authorized users for the app will be sent to the same endpoint. While this technique will be supported soon, for now, a workaround is to perform polling on the endpoint.