NJS + NPM + TS

.eslintrc.json

{
  "extends": [
    "eslint:recommended",
    "plugin:@typescript-eslint/recommended",
    "plugin:prettier/recommended"
  ],
  "ignorePatterns": ["**/node_modules/", "/dist/", "/lib/"],
  "parserOptions": {
    "sourceType": "module"
  },
  "rules": {
    "@typescript-eslint/no-unused-vars": [
      "warn",
      {
        "argsIgnorePattern": "^_",
        "varsIgnorePattern": "^_",
        "caughtErrorsIgnorePattern": "^_"
      }
    ]
  },
  "root": true
}

.prettierrc.yml

# style settings, see https://prettier.io/docs/en/options.html
semi: false
singleQuote: true
trailingComma: es5
tabWidth: 2

babel.config.js

'use strict'
// @ts-check

/** @type {babel.ConfigFunction} */
// eslint-disable-next-line no-undef
module.exports = (api) => ({
  presets: [
    // Transpile modern JavaScript into code compatible with njs.
    // This is used only for building the dist bundle with Rollup.
    ...(api.env('njs') ? ['babel-preset-njs'] : []),
    // Parse TypeScript syntax and transform it to JavaScript (i.e. it strips
    // type annotations, but does not perform type checking).
    [
      '@babel/preset-typescript',
      {
        allowDeclareFields: true,
      },
    ],
  ],

  plugins: [
    ...(!api.caller((c) => c && c.supportsStaticESM)
      ? [
          // Transform ES modules to CommonJS if needed  needed for Mocha tests).
          // Mocha, babel-node, babel/register etc. don't understand ES module
          // syntax, so we have to transform it to CommonJS.
          // This is not used with Rollup.
          '@babel/plugin-transform-modules-commonjs',
        ]
      : []),
    ...(api.env('mocha')
      ? [
          // Transform power-assert. This is used only for Mocha tests.
          'babel-plugin-empower-assert',
          'babel-plugin-espower',
        ]
      : []),
  ],
})

Dockerfile

# syntax=docker/dockerfile:1
FROM node:18 AS builder
WORKDIR /app
COPY package.json package-lock.json ./
RUN --mount=type=cache,target=/app/.npm \
    npm set cache /app/.npm && \
    npm ci
COPY . .
RUN npm run build

FROM nginx:1.24.0
COPY --from=builder /app/dist/acme.js /usr/lib/nginx/njs_modules/mymodule.js
# COPY ./examples/nginx.conf /etc/nginx/nginx.conf

# install the latest njs > 0.8.0
RUN --mount=type=cache,target=/var/cache/apt <<EOF
    set -eux
    export DEBIAN_FRONTEND=noninteractive
    apt -qq update
    apt install -qq  --yes --no-install-recommends --no-install-suggests \
        curl gnupg2 ca-certificates lsb-release debian-archive-keyring
    update-ca-certificates
    curl https://nginx.org/keys/nginx_signing.key | gpg --dearmor \
        | tee /usr/share/keyrings/nginx-archive-keyring.gpg >/dev/null
    gpg --dry-run --quiet --no-keyring --import --import-options import-show \
        /usr/share/keyrings/nginx-archive-keyring.gpg
    echo "deb [signed-by=/usr/share/keyrings/nginx-archive-keyring.gpg] \
        http://nginx.org/packages/mainline/debian `lsb_release -cs` nginx" \
    | tee /etc/apt/sources.list.d/nginx.list
    apt update -qq
    apt install -qq  --yes --no-install-recommends --no-install-suggests \
        nginx-module-njs
    apt remove --purge --auto-remove --yes
    rm -rf /var/lib/apt/lists/* /etc/apt/sources.list.d/nginx.list
EOF

package.json

{
  "name": "NAME",
  "version": "1.0.0",
  "description": "## How do I use this template?",
  "main": "dist/main.js",
  "files": [
    "dist",
    "src"
  ],
  "keywords": [],
  "author": "",
  "engines": {
    "node": ">= 14.15"
  },
  "scripts": {
    "build": "rollup -c --environment NODE_ENV:dev",
    "clean": "rimraf dist/* lib/* node_modules/.cache/*",
    "lint": "run-p lint:*",
    "lint:eslint": "npx eslint .",
    "start": "run-p watch start-nginx",
    "start-nginx": "start-nginx --version 1.25.x --port 8090 --watch dist/ integration-tests/nginx.conf",
    "test": "run-p test:*",
    "test:unit": "mocha --config ./unit-tests/.mocharc.js",
    "test:integration": "rollup -c && mocha --config ./integration-tests/.mocharc.js",
    "watch": "rollup -c --watch --no-watch.clearScreen",
    "prettier": "prettier --check --write src/"
  },
  "dependencies": {
    "asn1js": "^3.0.5",
  },
  "devDependencies": {
    "@babel/core": "^7.21.8",
    "@babel/plugin-transform-modules-commonjs": "^7.21.5",
    "@babel/preset-typescript": "^7.21.5",
    "@babel/register": "^7.21.0",
    "@rollup/plugin-babel": "^5.3.1",
    "@rollup/plugin-commonjs": "^18.1.0",
    "@rollup/plugin-json": "^6.0.0",
    "@rollup/plugin-node-resolve": "^11.2.1",
    "@types/babel__core": "^7.20.0",
    "@types/mocha": "^8.2.3",
    "@types/rollup-plugin-add-git-msg": "^1.1.1",
    "@typescript-eslint/eslint-plugin": "^4.33.0",
    "@typescript-eslint/parser": "^4.33.0",
    "babel-plugin-empower-assert": "^2.0.0",
    "babel-plugin-espower": "^3.0.1",
    "babel-preset-njs": "^0.2.1",
    "babel-register-ts": "^7.0.0",
    "eslint": "^7.32.0",
    "eslint-config-prettier": "^8.8.0",
    "eslint-plugin-prettier": "^4.2.1",
    "got": "^11.8.6",
    "mocha": "^10.2.0",
    "mocha-suite-hooks": "^0.1.0",
    "nginx-testing": "^0.4.0",
    "njs-types": "^0.8.0",
    "npm-run-all": "^4.1.5",
    "power-assert": "^1.6.1",
    "prettier": "^2.8.8",
    "rimraf": "^3.0.2",
    "rollup": "^2.79.1",
    "rollup-plugin-add-git-msg": "^1.1.0",
    "typescript": "~4.2.4"
  }
}

rollup.config.js

// @ts-check
import addGitMsg from 'rollup-plugin-add-git-msg'
import babel from '@rollup/plugin-babel'
import commonjs from '@rollup/plugin-commonjs'
import resolve from '@rollup/plugin-node-resolve'
import json from '@rollup/plugin-json'
import pkg from './package.json'

// List of njs built-in modules.
const njsExternals = ['crypto', 'fs', 'querystring']
// eslint-disable-next-line no-undef
const isEnvProd = process.env.NODE_ENV === 'production'

/**
 * Plugin to fix syntax of the default export to be compatible with njs.
 * (https://github.com/rollup/rollup/pull/4182#issuecomment-1002241017)
 *
 * @return {import('rollup').OutputPlugin}
 */
const fixExportDefault = () => ({
  name: 'fix-export-default',
  renderChunk: (code) => ({
    code: code.replace(/\bexport { (\S+) as default };/, 'export default $1;'),
    map: null,
  }),
})

/**
 * @type {import('rollup').RollupOptions}
 */
const options = {
  input: 'src/index.ts',
  external: njsExternals,
  plugins: [
    // Transpile TypeScript sources to JS.
    babel({
      babelHelpers: 'bundled',
      envName: 'njs',
      extensions: ['.ts', '.mjs', '.js'],
    }),
    // Resolve node modules.
    resolve({
      extensions: ['.mjs', '.js', '.json', '.ts'],
    }),
    json(),
    // Convert CommonJS modules to ES6 modules.
    commonjs(),
    // Fix syntax of the default export.
    fixExportDefault(),
    // Plugins to use in production mode only.
    ...(isEnvProd
      ? [
          // Add git tag, commit SHA, build date and copyright at top of the file.
          addGitMsg(),
        ]
      : []),
  ],
  output: {
    file: pkg.main,
    format: 'es',
  },
}
export default options

src-index.ts

// now you can use the NPM dep
// import { *} from name


async function hello(r: NginxHTTPRequest): Promise<void> {
  return r.return(200, "Hello world")
}
  
  
export default {
  hello,
}

tsconfig.json

{
  "compilerOptions": {
    /* Visit https://aka.ms/tsconfig.json to read more about this file */
    /* Basic Options */
    "incremental": true,                      /* Enable incremental compilation */
    "target": "ES2020",                       /* Specify ECMAScript target version: 'ES3' (default), 'ES5', 'ES2015', 'ES2016', 'ES2017', 'ES2018', 'ES2019', 'ES2020', or 'ESNEXT'. */
    "module": "commonjs",                     /* Specify module code generation: 'none', 'commonjs', 'amd', 'system', 'umd', 'es2015', 'es2020', or 'ESNext'. */
    // "lib": []                              /* Specify library files to be included in the compilation. */
    "allowJs": true, /* Allow javascript files to be compiled. */
    // "checkJs": true,                       /* Report errors in .js files. */
    // "jsx": "preserve",                     /* Specify JSX code generation: 'preserve', 'react-native', or 'react'. */
    // "declaration": true,                   /* Generates corresponding '.d.ts' file. */
    // "declarationMap": true,                /* Generates a sourcemap for each corresponding '.d.ts' file. */
    // "sourceMap": true,                     /* Generates corresponding '.map' file. */
    // "outFile": "./",                       /* Concatenate and emit output to single file. */
    // "outDir": "./",                        /* Redirect output structure to the directory. */
    // "rootDir": "./",                       /* Specify the root directory of input files. Use to control the output directory structure with --outDir. */
    // "composite": true,                     /* Enable project compilation */
    "tsBuildInfoFile": "./node_modules/.cache/tsc/root.tsbuildinfo", /* Specify file to store incremental compilation information */
    // "removeComments": true,                /* Do not emit comments to output. */
    "noEmit": true,                           /* Do not emit outputs. */
    // "importHelpers": true,                 /* Import emit helpers from 'tslib'. */
    // "downlevelIteration": true,            /* Provide full support for iterables in 'for-of', spread, and destructuring when targeting 'ES5' or 'ES3'. */
    // "isolatedModules": true,               /* Transpile each file as a separate module (similar to 'ts.transpileModule'). */
    /* Strict Type-Checking Options */
    "strict": true,                           /* Enable all strict type-checking options. */
    "noImplicitAny": true,                    /* Raise error on expressions and declarations with an implied 'any' type. */
    "strictNullChecks": true,                 /* Enable strict null checks. */
    "strictFunctionTypes": true,              /* Enable strict checking of function types. */
    "strictBindCallApply": true,              /* Enable strict 'bind', 'call', and 'apply' methods on functions. */
    "strictPropertyInitialization": true,     /* Enable strict checking of property initialization in classes. */
    "noImplicitThis": true,                   /* Raise error on 'this' expressions with an implied 'any' type. */
    "alwaysStrict": true,                     /* Parse in strict mode and emit "use strict" for each source file. */
    /* Additional Checks */
    "noUnusedLocals": true,                   /* Report errors on unused locals. */
    "noUnusedParameters": true,               /* Report errors on unused parameters. */
    "noImplicitReturns": true,                /* Report error when not all code paths in function return a value. */
    "noFallthroughCasesInSwitch": true,       /* Report errors for fallthrough cases in switch statement. */
    // "noUncheckedIndexedAccess": true,      /* Include 'undefined' in index signature results */
    // "noPropertyAccessFromIndexSignature": true,  /* Require undeclared properties from index signatures to use element accesses. */
    /* Module Resolution Options */
    "moduleResolution": "node",               /* Specify module resolution strategy: 'node' (Node.js) or 'classic' (TypeScript pre-1.6). */
    // "baseUrl": "./",                       /* Base directory to resolve non-absolute module names. */
    // "paths": {},                           /* A series of entries which re-map imports to lookup locations relative to the 'baseUrl'. */
    // "rootDirs": [],                        /* List of root folders whose combined content represents the structure of the project at runtime. */
    // "typeRoots": [],                       /* List of folders to include type definitions from. */
    // "types": [],                           /* Type declaration files to be included in compilation. */
    "allowSyntheticDefaultImports": true,     /* Allow default imports from modules with no default export. This does not affect code emit, just typechecking. */
    // "esModuleInterop": true,               /* Enables emit interoperability between CommonJS and ES Modules via creation of namespace objects for all imports. Implies 'allowSyntheticDefaultImports'. */
    // "preserveSymlinks": true,              /* Do not resolve the real path of symlinks. */
    // "allowUmdGlobalAccess": true,          /* Allow accessing UMD globals from modules. */
    "resolveJsonModule": true,                /* Include modules imported with '.json' extension. */
    /* Source Map Options */
    // "sourceRoot": "",                      /* Specify the location where debugger should locate TypeScript files instead of source locations. */
    // "mapRoot": "",                         /* Specify the location where debugger should locate map files instead of generated locations. */
    // "inlineSourceMap": true,               /* Emit a single file with source maps instead of having a separate file. */
    // "inlineSources": true,                 /* Emit the source alongside the sourcemaps within a single file; requires '--inlineSourceMap' or '--sourceMap' to be set. */
    /* Experimental Options */
    // "experimentalDecorators": true,        /* Enables experimental support for ES7 decorators. */
    // "emitDecoratorMetadata": true,         /* Enables experimental support for emitting type metadata for decorators. */
    /* Advanced Options */
    "skipLibCheck": true,                     /* Skip type checking of declaration files. */
    "forceConsistentCasingInFileNames": true, /* Disallow inconsistently-cased references to the same file. */
  },
  "include": [
    "./integration-tests",
    "./unit-tests",
    "./*.js",
  ],
  "references": [
    {
      "path": "./src"
    },
  ],
}