Firebase Firestore: Update Document

 
export default async function main(args) {
 /**
  * IMPORTANT
  *
  * Use with CAUTION. This is a destructive operation.
  *
  * Please read the Query Parameters documentation carefully
  *
  * https://firebase.google.com/docs/firestore/reference/rest/v1/projects.databases.documents/patch#query-parameters
  */

  // Validate input variables from args - find the "validateInputs" function below
  const invalidFieldTrace = validateInputs(args)

  if (invalidFieldTrace) return invalidFieldTrace;

  // Extract input variables from args (destructuring)
  const {
    reservationType,
    updateField,
    firebaseProjectId,
    firebaseDatabase, // Default database name is '(default)'
    firebaseCollection,
    firebaseDocumentId,
    firebaseApiKey,
  } = args.inputVars;

  /**
   * Build the payload for updating a new document in Firebase
   *
   * Check Firebase documentation to learn what data types are available
   *
   * - https://firebase.google.com/docs/firestore/reference/rest/v1/projects.databases.documents/patch
   * - https://firebase.google.com/docs/firestore/reference/rest/v1/DocumentMask
   * - https://firebase.google.com/docs/firestore/reference/rest/Shared.Types/ArrayValue#Value
   */
  const payload = {
    fields: {
      [updateField]: { // Field name
        stringValue: reservationType // New Value
      },
    }
  };


  /**
   * IMPORTANT
   *
   * Define the fields you want to update, otherwise 
   * you will override the existent information in the document
   *
   * Adapt or add as many fields as you want
   *
   * The value of "updateField" should match the key name in payload.fields
   */
  const updateFields = [updateField]
  // Generate the update mask string
  const updateMask = updateFields
    .map(field => `updateMask.fieldPaths=${field}`)
    .join('&')

  /**
   * Define the URL for Firebase REST operations
   */
  const baseUrl = `https://firestore.googleapis.com/v1`;
  const pathUrl = `projects/${firebaseProjectId}/databases/${firebaseDatabase}/documents/${firebaseCollection}/${firebaseDocumentId}`
  const endpointUrl = `${baseUrl}/${pathUrl}?${updateMask}&key=${firebaseApiKey}`

  /**
   * Configure the fetch request
   *
   * Get your Firebase Web API Key from the project settings
   *
   * https://console.firebase.google.com/project/YOUR_PROJECT_ID/settings/general
   */
  const config = {
    method: 'PATCH',
    headers: {
      'Content-Type': 'application/json',
    },
    body: JSON.stringify(payload)
  };

  try {
    // Make the API call
    const response = await fetch(endpointUrl, config);

    // Check if the response status is OK
    if (!response.ok) {
      throw new Error(`HTTP status code ${response.status}`);
    }

    // Extract the JSON body from the response
    const responseBody = response.json;

    // Validate the responseBody structure as expected
    if (!responseBody || typeof responseBody !== 'object') {
      throw new Error("Invalid or missing response body");
    }

    // Extract data from the response
    const document = responseBody;

    // Create the success return trace with extracted data
    return {
      outputVars: {
        document: JSON.stringify(document),
      },
      next: {
        path: 'success'
      },
      trace: [
        {
          type: "debug", 
          payload: {
            message: 'Firebase API call successful'
          }
        },
        { 
          type: "debug", 
          payload: {
            message: 'Document updated'
          }
        },
        {
          type: "debug", 
          payload: {
            message: JSON.stringify(document),
          }
        },
      ]
    };
  } catch (error) {
    return {
      next: {
        path: 'error'
      },
      trace: [{
        type: "debug",
        payload: {
          message: `Firebase API call error: ${error.message}`
        }
      }]
    };
  }

  /**
   * Here we validate all the inputs of the Voiceflow function
   *
   * The function can be used in the first lines of the code
   * because of a Javascript concept called hoisting
   *
   * Read more: https://developer.mozilla.org/en-US/docs/Glossary/Hoisting
   */
  function validateInputs(args) {
    // Extract input variables from args (destructuring)
    const {
      reservationType,
      updateField,
      firebaseProjectId,
      firebaseDatabase,
      firebaseCollection,
      firebaseDocumentId,
      firebaseApiKey,
    } = args.inputVars;
  
    // Validate that reservationType variable is provided
    if (!reservationType) {
      return {
        next: { path: 'error' },
        trace: [{ type: "debug", payload: { message: "Missing required input variable: reservationType" } }]
      };
    }
  
    // Validate that updateField variable is provided
    if (!updateField) {
      return {
        next: { path: 'error' },
        trace: [{ type: "debug", payload: { message: "Missing required input variable: updateField" } }]
      };
    }
  
    // Validate that firebaseProjectId variable is provided
    if (!firebaseProjectId) {
      return {
        next: { path: 'error' },
        trace: [{ type: "debug", payload: { message: "Missing required input variable: firebaseProjectId" } }]
      };
    }
  
    // Validate that firebaseDatabase variable is provided
    if (!firebaseDatabase) {
      return {
        next: { path: 'error' },
        trace: [{ type: "debug", payload: { message: "Missing required input variable: firebaseDatabase" } }]
      };
    }
  
    // Validate that firebaseCollection variable is provided
    if (!firebaseCollection) {
      return {
        next: { path: 'error' },
        trace: [{ type: "debug", payload: { message: "Missing required input variable: firebaseCollection" } }]
      };
    }
  
    // Validate that firebaseDocumentId variable is provided
    if (!firebaseDocumentId) {
      return {
        next: { path: 'error' },
        trace: [{ type: "debug", payload: { message: "Missing required input variable: firebaseDocumentId" } }]
      };
    }
  
    // Validate that firebaseApiKey variable is provided
    if (!firebaseApiKey) {
      return {
        next: { path: 'error' },
        trace: [{ type: "debug", payload: { message: "Missing required input variable: firebaseApiKey" } }]
      };
    }

    return null
  }
}