Google Apps & TypeScript Project Template

This repository provides a simple template to start a new Google Apps Script project with TypeScript. Building, linting, formatting, and pushing to Google Apps are all built in.

The project is set up with a TypeScript configuration that transforms your TypeScript files in the src directory into JavaScript files in the build directory. It's not enough to upload those files as-is to Google Apps, however, because Apps Script doesn't support installing and running dependencies, and uploaded files are run in random order - they aren't linked together at all. To solve this problem, a second build step uses Webpack to combine all files and depdendencies into a single minified Code.js file, which is the only file that is actually pushed to Google Apps.

Getting Started

1. Click "Use This Template" to start a new repository. Clone your new repo and open a terminal in the local directory. This template includes some configuration for VSCode, but you can use any editor.
2. Ensure Node.js is installed on your system, then install all of the dependencies by running npm install. Alternatively, start a Codespace in your new repository and dependencies will be installed automatically.
3. Start a new Google Apps Script project by going to https://script.google.com/home and clicking New project. You can also start a project tied directly to a specific Google Apps file by opening the file and clicking Tools -> Script Editor.
4. Click the gear icon in the Google Apps Script editor sidebar. Copy the Script ID.
5. Replace SCRIPT_ID in .clasp.json with your project's ID. This ID is not a secret - you can safely commit it to your repository.
6. Write your TypeScript code in the src folder. Note that index.ts is the entrypoint for your project. Only what is imported into the index.ts file will be compiled into the script.
7. Optional: lint your code with npm run lint and/or auto-format your code with npm run format. Typically you will want to install the ESLint and/or Prettier extensions in your preferred code editor.
8. Deploy your code to Google Apps:
   • Manually:
     1. Log in to Google Apps Script by running npm run login. Make sure to use the same account you used to make the Google Apps Script project. You only need to do this once.
     2. Compile the TypeScript files into a single JavaScript file and push it to Google Apps by running npm run deploy. Run this every time you make changes.
   • Automatically: You can configure GitHub Actions to automatically deploy your code every time you push it (or every time you create a new release). This is advantageous because you can be sure your repository will always have the same code that is deployed to Google Apps. However, Google's Clasp tool is not designed to authenticate in CI environments and so this takes some more complicated setup and isn't included in this template by default. One option for this might be ericanastas/deploy-google-app-script-action.

Available Scripts

You can run the following scripts by opening the project directory in your terminal (as long as you have Node & npm installed):

• npm install Install all required dependencies.
• npm run build Build your project to ensure it compiles properly.
• npm run format Format your code automatically using Prettier.
• npm run lint Check your code for common errors using ESLint.
• npm run login Login to the Google Apps Script client so you can push/pull. You will need to run this once on each device you use.
• npm run pull Fetch the latest changes from Google Apps Script. You should only need to do this if you change the project settings.
• npm run push Build your project and push it to Google Apps in one step. The first time you run this, you will be prompted to log in to your Google account. This command will automatically update any test deployments.
• npm run deploy Build and push your code, then create a new versioned deployment.

You can also run any Clasp command with npx clasp <command>.

Automated GitHub Workflow

The template comes with a built-in configuration file for GitHub Workflows. The workflow is configured to run on every push to the main branch as well as on every Pull Request as a Check, and it simply checks the code to ensure that it passes linting and is buildable (has no type/syntax errors). This is known as continuous integration and provides a form of automated testing to ensure that your project's code is always valid.

For larger projects where more than one developer will be collaborating, it is reccomended to protect the main branch and only allow changes to it through Pull Requests in which all checks pass. You can learn more about this from GitHub's help articles.

If you would like to disable the workflow, simply delete the checks.yml file.

Development Notes

The following notes have important information for writing code for Google Apps Script using this template. Please read through them before you start.

Important: Exposing Functions to Google Apps Script

In order for your Google Apps to run any of your code, you'll need to expose one or more functions to the engine. In the traditional Google Apps Script environment, you'd do this by declaring global functions, however in this setup there is no concept of 'global' as all files are modules.

Instead, only functions exported from index.ts will be available to Google Apps Script. Any function exported from index.ts will be accessible by all triggers and anywhere else Google Apps might need to call your function, such as from a custom menu.

Due to a bug in the Webpack plugin, only exports in export {...} form are supported:

// ❌ Does NOT work
export function bad1() { /* ... */ }

export const bad2 = () => { /* ... */ }

// ✅ Does work:
export {good1} from "./good1.ts"

function good2() { /* ... */ }
const good3 = () => { /* ... */ }

export {good2, good3}

Examples for all the simple triggers are given in index.ts.

For cleaner, more usable code, it may be useful to reference functions by their name property instead of hardcoding the name into code. For example:

const createButton = CardService.newTextButton()
  .setText("Create")
  .setOnClickAction(
     // Here we use `onClickCreateEvent.name` instead of hardcoding `"onClickCreateEvent"`
    CardService.newAction().setFunctionName(onClickCreateEvent.name)
  );

Circular Dependencies

Circular dependencies (files that depend on each other in a circular manner) can cause unexpected issues like "X is not a function" or "X is not defined". If you are seeing these errors in your project and you know they are wrong, try checking for circular dependencies using madge (not included in this template):

1. Install madge globally with npm i --global madge.
2. Check for circular dependencies with madge src/index.ts --circular.

Included Files

• .github
  • workflows All GitHub workflows are configured using YAML files in this directory.
    • checks.yml This is where the continuous integration workflow is configured.
• src This is where you'll put all your TypeScript files.
  • example.ts Gives an example of how to export something from a local file.
  • index.ts Provides you with the five basic triggers prebuilt, as well as an example of how to import from a local file.
• .clasp.json Provides the configuration for Clasp, the command-line tool which pushes code to Google Apps Script.
• .claspignore Tells Clasp to ignore every file except for Code.js, appsscript.json, and readme_appsscript.md.
• .gitignore Tells Git to ignore output files and node_modules.
• .prettierrc Configures Prettier, the code formatter.
• appsscript.json Controls the project setup and Apps Script environment. You can change the exception logger, but don't change the runtime version.
• package.json Lists the project dependencies and scripts.
• readme_appsscript.md If anyone opens your project in the Apps Script editor, they'll just see a jumbled file. This note helps them realize that the project should be edited outside of that environment.
• readme.md This file.
• tsconfig.json Configures the TypeScript compiler to enable strict mode and compile to CommonJS modules from the src folder to the build folder.
• webpack.config.js Configures Webpack to take files from the build folder and dependencies and merge them all into a single Code.js file.