title: Reference error firestore is not defined in firebase cloud function when using firebase admin sdk
body: <p>I have a cloud function in which I am listening to the onCreate event of a firestore collection. When the cloud function is triggered I am getting a reference error. Below are the cloud function code and the error.</p>
  <pre class="lang-js prettyprint-override"><code>const functions = require('firebase-functions')
  const serviceAccount = require('./serviceAccountKey.json')
  const admin = require('firebase-admin')
  const { firestore } = require('firebase-admin')
  
  admin.initializeApp({
    credential: admin.credential.cert(serviceAccount),
    databaseURL: 'https://my-app-id.firebaseio.com', // Here I have replaced my real id for privacy
  })
  
  const db = admin.firestore()
  
  exports.handleDiscussionReplyAdded = functions.firestore
    .document('/discussions/{discussionId}/replies/{replyId}')
    .onCreate(async (snap, context) =&gt; {
      try {
        // 1. Creating a ref to parent chat doc
        const discussionRef = db
          .collection('discussions')
          .doc(context.params.discussionId)
  
        // 2. Updating the data
        await discussionRef.update({
          totalReplies: firestore.FieldValue.increment(1),
        })
  
        // Return true if everything went fine
        return true
      } catch (error) {
        // Return error if something went wrong
        functions.logger.error(`Error: ${JSON.stringify(error)}`)
        return error
      }
    })
  </code></pre>
  <pre class="lang-js prettyprint-override"><code>{
    &quot;severity&quot;: &quot;ERROR&quot;,
    &quot;message&quot;: &quot;ReferenceError: firestore is not defined\n    at /Users/syedalirazabokhari/Desktop/Development/React/omanshopping/functions/index.js:23:23\n    at cloudFunction (/Users/syedalirazabokhari/Desktop/Development/React/omanshopping/functions/node_modules/firebase-functions/lib/cloud-functions.js:134:23)\n    at /usr/local/lib/node_modules/firebase-tools/lib/emulator/functionsEmulatorRuntime.js:590:16\n    at runFunction (/usr/local/lib/node_modules/firebase-tools/lib/emulator/functionsEmulatorRuntime.js:577:15)\n    at runBackground (/usr/local/lib/node_modules/firebase-tools/lib/emulator/functionsEmulatorRuntime.js:589:11)\n    at processBackground (/usr/local/lib/node_modules/firebase-tools/lib/emulator/functionsEmulatorRuntime.js:572:11)\n    at invokeTrigger (/usr/local/lib/node_modules/firebase-tools/lib/emulator/functionsEmulatorRuntime.js:647:19)\n    at handleMessage (/usr/local/lib/node_modules/firebase-tools/lib/emulator/functionsEmulatorRuntime.js:734:15)\n    at processTicksAndRejections (internal/process/task_queues.js:93:5)&quot;
  }
  </code></pre>
  <p>I tried to debug the issue but unable to resolve. I have also updated the firebase-admin to the latest version 9.5.0 as of now.</p>