typescript.md

Typescript

This guide is an example of how to develop a function in Typescript with the Functions Framework.

1. Create a new Node.js project using the npm CLI.

   mkdir typescript-function && cd typescript-function
   npm init -y

2. Install the required packages:

   npm install @google-cloud/functions-framework
   npm install --save-dev typescript

3. Create a tsconfig.json in the root directory of your project with the following contents:

   {
     "compilerOptions": {
       "target": "es2016",
       "module": "commonjs",
       "esModuleInterop": true,
       "strict": true,
       "outDir": "dist"
     },
     "include": ["src/**/*"],
     "exclude": ["node_modules"]
   }

4. Update your package.json with scripts for building and running your application:

   {
     "main": "dist/index.js",
     "scripts": {
       "build": "tsc",
       "start": "functions-framework --target=TypescriptFunction",
       "prestart": "npm run build",
       "gcp-build": "npm run build"
     },
     ...
   }

   • The main field must be configured to the compiled source code file that contains your function source.
   • The gcp-build script is run when deploying your application Google Cloud Functions. It allows you to configure build steps that depend on devDependencies.

5. Create a .gitignore that ensures your node_modules and compiled code are not checked into source control and are not uploaded when you deploy to Google Cloud Functions.

   node_modules/
   dist/
   

6. Create a src/index.ts file with your function source code.

   Example Typescript HTTP Function

   import * as ff from '@google-cloud/functions-framework';
   
   ff.http('TypescriptFunction', (req: ff.Request, res: ff.Response) => {
     res.send('OK');
   });

   Example Typescript CloudEvent Function

   The cloudEvent function registration method accepts a template type that can be used to annotate the event payload type you expect.

   import * as ff from '@google-cloud/functions-framework';
   
   interface PubSubData {
     subscription: string;
     message: {
       messageId: string;
       publishTime: string;
       data: string;
       attributes?: {[key: string]: string};
     };
   }
   
   ff.cloudEvent<PubSubData>('TypescriptFunction', ce => {
     console.log(ce.data?.message.messageId);
   });

Deploying with the gcloud CLI

If you correctly configured the main field and gcp-build script in your package.json you can deploy to Google Cloud Functions as you would any other Javascript function:

gcloud functions deploy TypescriptFunction \
--runtime nodejs16 \
--trigger-http