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Overview

Firestore Cloud Functions allow you to run backend code in response to events triggered by Firestore operations. The getChangeType utility is designed to work seamlessly within this environment, identifying whether a document in Firestore has been created, updated, or deleted. This enables precise and effective event handling in cloud functions.

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Change Types

• create: Indicates a new document was added.
• update: Represents updates to an existing document.
• delete: Occurs when a document is removed.

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Usage in Cloud Functions

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Setting up a Firestore Trigger

To use getChangeType in a Firestore Cloud Function:

import * as functions from 'firebase-functions'
import { firestore } from 'firebase-admin'
import { getChangeType } from '@firebridge/cloud'

// Cloud Function listening to changes in a specific collection
export const onDocumentChange = functions.firestore
  .document('/your-collection/{docId}')
  .onWrite((change, context) => {
    // Determine the type of change
    const changeType = getChangeType(change)

    switch (changeType) {
      case 'create':
        // Handle creation logic
        console.log(`New document created: ${context.params.docId}`)
        break
      case 'update':
        // Handle update logic
        console.log(`Document updated: ${context.params.docId}`)
        break
      case 'delete':
        // Handle deletion logic
        console.log(`Document deleted: ${context.params.docId}`)
        break
    }
  })

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DocumentChangeType Explanation

The DocumentChangeType type alias simplifies working with Firestore changes in TypeScript, ensuring you always handle the correct type of document change.

type DocumentChangeType = 'create' | 'update' | 'delete'

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Practical Applications

• Data Validation: Validate or transform data when a new document is created or updated.
• Notification Systems: Trigger notifications on data changes, such as sending an email when a new document is added.
• Data Synchronization: Sync data with other systems or databases on document changes.

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Best Practices

• Thoroughly test your Cloud Functions to ensure they behave as expected for each type of document change.
• Optimize your function’s execution time and resource usage, especially if your Firestore operations are frequent and large in scale.
• Document the purpose and expected behavior of your Cloud Functions for future reference and maintenance.

With these guidelines, you can effectively integrate getChangeType into your Firestore Cloud Functions, enhancing your application’s responsiveness and efficiency in handling real-time data changes.