[[["わかりやすい","easyToUnderstand","thumb-up"],["問題の解決に役立った","solvedMyProblem","thumb-up"],["その他","otherUp","thumb-up"]],[["必要な情報がない","missingTheInformationINeed","thumb-down"],["複雑すぎる / 手順が多すぎる","tooComplicatedTooManySteps","thumb-down"],["最新ではない","outOfDate","thumb-down"],["翻訳に関する問題","translationIssue","thumb-down"],["サンプル / コードに問題がある","samplesCodeIssue","thumb-down"],["その他","otherDown","thumb-down"]],["最終更新日 2025-09-04 UTC。"],[],[],null,["\u003cbr /\u003e\n\nFor developers who prefer to write functions in TypeScript,\nCloud Functions provides two types of support:\n\n- Create and configure TypeScript projects for automatic transpilation at initialization (`firebase init functions`).\n- Transpile existing TypeScript source to JavaScript at deploy time via a [predeploy hook](/docs/cli#hooks).\n\nFollowing instructions in this guide, you can migrate an existing\nJavaScript project to TypeScript and continue deploying functions using a\npredeploy hook to transpile your source code.\nTypeScript offers many benefits over vanilla JavaScript\nwhen writing functions:\n\n- TypeScript supports latest JavaScript features like async/await, simplifying promise management\n- A Cloud Functions linter highlights common problems while you're coding\n- Type safety helps you avoid runtime errors in deployed functions\n\nIf you're new to TypeScript, see [TypeScript in 5 minutes](http://www.typescriptlang.org/docs/handbook/typescript-in-5-minutes.html).\n\nInitializing a new Cloud Functions project with TypeScript\n\nRun `firebase init functions` in a new directory. The tool gives you options to build\nthe project with JavaScript or TypeScript. Choose **TypeScript** to output the\nfollowing project structure: \n\n myproject\n +- functions/ # Directory containing all your functions code\n |\n +- package.json # npm package file describing your Cloud Functions code\n |\n +- tsconfig.json\n |\n +- .eslintrc.js # Optional file if you enabled ESLint\n +- tsconfig.dev.json # Optional file that references .eslintrc.js\n |\n +- src/ # Directory containing TypeScript source\n | |\n | +- index.ts # main source file for your Cloud Functions code\n |\n +- lib/\n |\n +- index.js # Built/transpiled JavaScript code\n |\n +- index.js.map # Source map for debugging\n\nOnce initialization is complete, uncomment the sample in index.ts and run\n`npm run serve` to see a \"Hello World\" function in action.\n\nUsing an existing TypeScript project\n\nIf you have an existing TypeScript project, you can add a predeploy hook to\nmake sure your project is transpiled every time you deploy your code to\nCloud Functions for Firebase. You'll need a\nproperly formed `tsconfig.json` file and a Firebase project, and you'll need\nto make the following modifications to your Firebase configuration:\n\n1. Edit `package.json` to add a bash script to build your TypeScript project. For example:\n\n {\n \"name\": \"functions\",\n \"scripts\": {\n \"build\": \"npm run lint && tsc\"\n }\n ...\n\n2. Edit `firebase.json` to add a predeploy hook to run the build script. For example:\n\n {\n \"functions\": {\n \"predeploy\": \"npm --prefix functions run build\",\n }\n }\n\nWith this configuration, a `firebase deploy --only functions` command\nbuilds your TypeScript code and deploys it as functions.\n\nMigrating an existing JavaScript project to TypeScript\n\nIf you have an existing Cloud Functions project that you initialized\nand developed in JavaScript, you can migrate it to\nTypeScript. You're strongly encouraged to create a git checkpoint or other\nbackup before starting.\n\n**To migrate an existing JavaScript Cloud Functions project:**\n\n1. Create a git checkpoint and save copies of your existing JavaScript source files.\n2. In the project directory, run `firebase init functions` and select `TypeScript` when prompted for a language for writing functions.\n3. When prompted whether to overwrite the existing `package.json` file, select **No** unless you are sure you don't want to keep the existing file.\n4. Delete `index.ts` in the directory `functions/src`, replacing it with your existing source code.\n5. In the `tsconfig.json` file created at initialization, set the compiler options to allow JavaScript: `\"allowJs\": true`.\n6. Copy your saved `package.json` file into the `functions` directory, and edit it to set `\"main\"` to `\"lib/index.js\"`.\n7. Also in `package.json`, add a build script for TypeScript like the following:\n\n {\n \"name\": \"functions\",\n \"scripts\": {\n \"build\": \"npm run lint && tsc\"\n }\n ...\n\n8. Add `\"typescript\"` as a dev dependency by running `npm install --save-dev typescript @typescript-eslint/eslint-plugin @typescript-eslint/parser`.\n\n9. For all dependencies, run `npm install --save @types/\u003cdependency\u003e`.\n\n10. Rewrite source code from .js to .ts as desired.\n\nEmulating TypeScript functions\n\nTo test TypeScript functions locally, you can use the emulation tools described\nin [Run functions locally](/docs/functions/local-emulator). It's important to\ncompile your code before using these tools, so make sure to run `npm run build`\ninside your functions directory before running `firebase emulators:start` or\n`firebase functions:shell`. Alternatively, run `npm run serve` or\n`npm run shell` as a shortcut; these commands both run the build and\nserve/start the functions shell.\n\nFunctions logs for TypeScript projects\n\nDuring `firebase deploy`, your project's `index.ts` is transpiled to `index.js`,\nmeaning that the Cloud Functions log will output line numbers from the\n`index.js` file and not the code you wrote. To make it easier for you to find the\ncorresponding paths and line numbers in `index.ts`,\n`firebase deploy` creates `functions/lib/index.js.map`. You can use this source\nmap in your preferred IDE or via a [node module](https://github.com/evanw/node-source-map-support)."]]
