initial

.gitignore

@@ -0,0 +1,4 @@
+node_modules
+dist
+assets
+*.tsbuildinfo

TODO.md

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+- storage drivers
+- auto-format
+- retention

morphus.yaml

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+allowedDomains:
+  - https://images.unsplash.com

package.json

@@ -0,0 +1,35 @@
+{
+  "name": "morphus",
+  "version": "0.1.0",
+  "description": "",
+  "author": "Niccolo Borgioli",
+  "license": "MIT",
+  "scripts": {
+    "build": "tsc",
+    "dev": "tsnd src"
+  },
+  "devDependencies": {
+    "@types/convict": "^6.1.1",
+    "@types/flat": "^5.0.2",
+    "@types/ms": "^0.7.31",
+    "@types/node": "^16.11.7",
+    "@types/sharp": "^0.29.3",
+    "ts-node-dev": "^1.1.8",
+    "typescript": "^4.4.4"
+  },
+  "dependencies": {
+    "caniuse-db": "^1.0.30001280",
+    "class-validator": "^0.13.1",
+    "convict": "^6.2.1",
+    "device-detector-js": "^3.0.0",
+    "fastify": "^3.23.1",
+    "fastify-caching": "^6.1.0",
+    "fastify-compress": "^3.6.1",
+    "fastify-cors": "^6.0.2",
+    "flat": "^5.0.2",
+    "ms": "^2.1.3",
+    "sharp": "^0.29.3",
+    "under-pressure": "^5.8.0",
+    "yaml": "^1.10.2"
+  }
+}

src/config.ts

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+import convict from 'convict'
+import yaml from 'yaml'
+
+export enum StorageType {
+  Local = 'local',
+  // S3 = 's3',
+  // GCS = 'gcs',
+  // Azure = 'azure',
+}
+
+export enum URLClean {
+  Off = 'off',
+  Fragment = 'fragment',
+  Query = 'query',
+}
+
+convict.addParser({ extension: ['yml', 'yaml'], parse: yaml.parse })
+const config = convict({
+  // Security
+  allowedDomains: {
+    doc: 'The domains that are allowed to be used as image sources',
+    format: Array,
+    default: [] as string[],
+    env: 'ALLOWED_DOMAINS',
+  },
+  cleanUrls: {
+    doc: 'Whether to clean URLs',
+    format: Object.values(URLClean),
+    default: URLClean.Fragment,
+    env: 'CLEAN_URLS',
+  },
+
+  // Caching
+  maxAge: {
+    doc: 'The maximum age of a cached image',
+    format: String,
+    default: '1d',
+    env: 'MAX_AGE',
+  },
+
+  storage: {
+    doc: 'The storage engine to use',
+    format: Object.values(StorageType),
+    default: StorageType.Local,
+    env: 'STORAGE',
+  },
+
+  // Local storage
+  assets: {
+    doc: 'The path to the assets folder',
+    format: String,
+    default: './assets',
+    env: 'ASSETS',
+  },
+})
+
+for (const file of ['morphus.yaml', 'morphus.yaml', 'morphus.json']) {
+  try {
+    config.loadFile(file)
+    break
+  } catch {}
+}
+
+export const Config = config.get()
+
+console.debug(Config)

src/controllers/index.ts

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+import {
+  IsDefined,
+  IsInt,
+  IsOptional,
+  IsPositive,
+  IsString,
+  IsUrl,
+  IsIn,
+  IsObject,
+  ValidateNested,
+} from 'class-validator'
+import { RouteHandlerMethod } from 'fastify'
+import sharp, { FitEnum, FormatEnum } from 'sharp'
+import { flatten, unflatten } from 'flat'
+import ms from 'ms'
+import DeviceDetector from 'device-detector-js'
+import Avif from 'caniuse-db/features-json/avif.json'
+import WebP from 'caniuse-db/features-json/webp.json'
+
+import { storage } from '../storage'
+import { transform } from '../transform'
+import { sha3, sortObjectByKeys, validateSyncOrFail } from '../utils/utils'
+import { Config, URLClean } from '../config'
+
+const detector = new DeviceDetector()
+
+export class ComplexParameter<N = string, T extends object = {}> {
+  @IsString()
+  name: N
+
+  @IsObject()
+  options: T
+
+  constructor(parameter: string) {
+    const [name, optionsRaw] = parameter.split('|')
+    if (!name) throw new Error('Invalid parameter')
+    this.name = name as any
+    this.options = {} as any
+    if (optionsRaw) {
+      for (const option of optionsRaw.split(',')) {
+        const [key, value] = option.split(':')
+        if (!key || !value) continue
+        // @ts-ignore
+        this.options[key] = ComplexParameter.ParseValue(value)
+      }
+    }
+    this.options = unflatten(this.options)
+  }
+
+  static ParseValue(value: string) {
+    if (value === 'true') return true
+    if (value === 'false') return false
+
+    const asNumber = Number(value)
+    if (!isNaN(asNumber)) return asNumber
+
+    return value
+  }
+}
+
+export enum ImageOperations {
+  resize,
+  flip,
+  flop,
+  affine,
+  sharpen,
+  median,
+  blur,
+  flatten,
+  gamma,
+  negate,
+  normalise,
+  normalize,
+  clahe,
+  convolve,
+  threshold,
+  boolean,
+  linear,
+  recomb,
+  modulate,
+}
+
+export enum ImageFormat {
+  jpeg,
+  png,
+  webp,
+  gif,
+  jp2,
+  tiff,
+  avif,
+  heif,
+  raw,
+}
+
+export class TransformQueryBase {
+  @IsString()
+  @IsUrl()
+  @IsDefined()
+  url!: string
+
+  @IsOptional()
+  @ValidateNested()
+  format?: ComplexParameter<keyof FormatEnum>
+
+  @IsOptional()
+  @IsIn(Object.values(sharp.fit))
+  resize?: keyof FitEnum
+
+  @IsOptional()
+  @IsInt()
+  @IsPositive()
+  width?: number
+
+  @IsOptional()
+  @IsInt()
+  @IsPositive()
+  height?: number
+
+  @ValidateNested()
+  op: ComplexParameter[] = []
+
+  hash: string
+
+  constructor(data: any, options: { ua?: string }) {
+    Object.assign(this, data)
+
+    if (this.width) this.width = parseInt(this.width as any)
+    if (this.height) this.height = parseInt(this.height as any)
+
+    this.op = Array.isArray(this.op) ? this.op : [this.op]
+    this.op = this.op.map((op) => new ComplexParameter(op as any))
+    if (this.format) this.format = new ComplexParameter(this.format as any)
+    if ((this.format?.name as string) === 'auto') {
+      if (!options.ua) throw new Error('cannot use auto format without user agent')
+      this.autoFormat(options.ua)
+    }
+
+    switch (Config.cleanUrls) {
+      case URLClean.Query: {
+        this.url = this.url.split('#')[0]!
+        this.url = this.url.split('?')[0]!
+        break
+      }
+      case URLClean.Fragment: {
+        this.url = this.url.split('#')[0]!
+        break
+      }
+    }
+
+    validateSyncOrFail(this)
+    if (this.resize) {
+      if (!this.width && !this.height) {
+        throw new Error('width or height is required when resizing')
+      }
+    }
+
+    this.hash = sha3(this.toString())
+  }
+
+  toString(): string {
+    const data = flatten(this) as Record<string, any>
+    return new URLSearchParams(sortObjectByKeys(data)).toString()
+  }
+
+  isAllowed(prefixes: string[]): boolean {
+    for (const prefix of prefixes) {
+      if (this.url.startsWith(prefix)) return true
+    }
+    return false
+  }
+
+  autoFormat(ua: string) {
+    const parsed = detector.parse(ua)
+    //https://caniuse.com/avif
+    console.log(parsed)
+    console.log(WebP)
+    // https://caniuse.com/webp
+  }
+}
+
+export const handler: RouteHandlerMethod = async (request, reply) => {
+  try {
+    const q = new TransformQueryBase(request.query, { ua: request.headers['user-agent'] })
+
+    if (!q.isAllowed(Config.allowedDomains)) {
+      reply.code(403).send({ error: 'Forbidden' })
+      return
+    }
+
+    // @ts-ignore
+    reply.etag(q.hash)
+    // @ts-ignore
+    reply.expires(new Date(Date.now() + ms(Config.maxAge)))
+
+    let stream: NodeJS.ReadableStream = (await storage.exists(q.hash))
+      ? await storage.readStream(q.hash)
+      : await transform(q)
+
+    reply.code(200).headers({
+      'Content-Type': `image/${q.format?.name}`,
+    })
+
+    return stream
+    // .send(stream)
+  } catch (err) {
+    reply.code(400).send(err)
+    return
+  }
+}

src/index.ts

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+// Require the framework and instantiate it
+import fastify from 'fastify'
+import compress from 'fastify-compress'
+import cors from 'fastify-cors'
+// @ts-ignore
+import cache from 'fastify-caching'
+import ms from 'ms'
+import underPressure from 'under-pressure'
+
+import { Config } from './config'
+import { handler } from './controllers'
+import { init } from './storage'
+
+init()
+
+const app = fastify({ logger: true })
+app.register(underPressure)
+app.register(cache, { expiresIn: ms(Config.maxAge) / 1000 })
+app.register(compress, { global: true })
+app.register(cors, { origin: true })
+
+app.get('/api/image', handler)
+
+async function start() {
+  try {
+    await app.listen(3000)
+  } catch (err) {
+    app.log.error(err)
+    process.exit(1)
+  }
+}
+start()

src/storage/index.ts

@@ -0,0 +1,27 @@
+import { Config, StorageType } from '../config'
+import { Local } from './local'
+
+export interface Storage {
+  read(path: string): Promise<Buffer>
+  write(path: string, data: Buffer): Promise<void>
+  exists(path: string): Promise<boolean>
+  delete(path: string): Promise<void>
+
+  readStream(path: string): Promise<NodeJS.ReadableStream>
+  writeStream(path: string): Promise<NodeJS.WritableStream>
+  // list(path: string): Promise<string[]>
+}
+
+export let storage: Storage
+
+export function init() {
+  if (!storage) {
+    switch (Config.storage) {
+      case StorageType.Local:
+        storage = new Local(Config.assets)
+        break
+      default:
+        throw new Error(`Unknown storage type: ${Config.storage}`)
+    }
+  }
+}

src/storage/local.ts

@@ -0,0 +1,76 @@
+import { resolve, join } from 'path'
+import fs from 'fs'
+
+import { Storage } from './'
+
+export class Local implements Storage {
+  constructor(private readonly root: string) {
+    this.root = resolve(root)
+  }
+
+  read(path: string): Promise<Buffer> {
+    const file = join(this.root, path)
+    return new Promise((resolve, reject) => {
+      fs.readFile(file, (err, data) => {
+        if (err) {
+          return reject(err)
+        }
+        resolve(data)
+      })
+    })
+  }
+
+  write(path: string, data: Buffer): Promise<void> {
+    const file = join(this.root, path)
+    return new Promise((resolve, reject) => {
+      fs.writeFile(file, data, (err) => {
+        if (err) {
+          return reject(err)
+        }
+        resolve()
+      })
+    })
+  }
+
+  exists(path: string): Promise<boolean> {
+    const file = join(this.root, path)
+    return new Promise((resolve, reject) => {
+      fs.access(file, fs.constants.F_OK, (err) => {
+        if (err) {
+          return resolve(false)
+        }
+        resolve(true)
+      })
+    })
+  }
+
+  delete(path: string): Promise<void> {
+    const file = join(this.root, path)
+    return new Promise((resolve, reject) => {
+      fs.unlink(file, (err) => {
+        if (err) {
+          return reject(err)
+        }
+        resolve()
+      })
+    })
+  }
+
+  readStream(path: string): Promise<NodeJS.ReadableStream> {
+    const file = join(this.root, path)
+    return new Promise((resolve, reject) => {
+      const stream = fs.createReadStream(file)
+      stream.on('error', reject)
+      resolve(stream)
+    })
+  }
+
+  writeStream(path: string): Promise<NodeJS.WritableStream> {
+    const file = join(this.root, path)
+    return new Promise((resolve, reject) => {
+      const stream = fs.createWriteStream(file)
+      stream.on('error', reject)
+      resolve(stream)
+    })
+  }
+}

src/transform/index.ts

@@ -0,0 +1,114 @@
+import { get } from 'https'
+import sharp from 'sharp'
+import { PassThrough } from 'stream'
+import { ComplexParameter, TransformQueryBase } from '../controllers'
+
+import { storage } from '../storage'
+import { sha3, splitter } from '../utils/utils'
+
+async function downloadImage(url: string): Promise<NodeJS.ReadableStream> {
+  const disk = await storage.writeStream(sha3(url))
+  return new Promise((resolve) => {
+    get(url, (res) => {
+      const out = new PassThrough()
+      splitter(res, out, disk)
+      resolve(out)
+    })
+  })
+}
+
+export async function getImage(url: string): Promise<NodeJS.ReadableStream> {
+  const id = sha3(url)
+  if (!(await storage.exists(id))) {
+    return await downloadImage(url)
+  }
+  return await storage.readStream(id)
+}
+
+function applyOperation(pipeline: sharp.Sharp, { name, options }: ComplexParameter<string, any>): sharp.Sharp {
+  switch (name) {
+    case 'negate':
+    case 'clahe':
+    case 'convolve':
+    case 'modulate':
+      return pipeline[name](options)
+    case 'flip':
+    case 'flop':
+    case 'normalise':
+    case 'normalize':
+    case 'greyscale':
+    case 'grayscale':
+    case 'removeAlpha':
+      return pipeline[name]()
+    case 'rotate': {
+      const { angle, ...rest } = options
+      return pipeline.rotate(angle, rest)
+    }
+    case 'threshold': {
+      const { threshold, ...rest } = options
+      return pipeline.threshold(threshold, rest)
+    }
+    case 'boolean': {
+      const { operator, operand, ...rest } = options
+      return pipeline.boolean(operand, operator, rest)
+    }
+    case 'linear':
+      return pipeline.linear(options.a, options.b)
+    case 'sharpen':
+      return pipeline.sharpen(options.sigma, options.flat, options.jagged)
+    case 'media':
+      return pipeline.median(options.size)
+    case 'blur':
+      return pipeline.blur(options.sigma)
+    case 'flatten':
+      return pipeline.flatten(options.background)
+    case 'gamma':
+      return pipeline.gamma(options.gamma)
+    case 'tint':
+      return pipeline.tint(options.rgb)
+    case 'pipelineColorspace':
+    case 'pipelineColourspace':
+      return pipeline.pipelineColorspace(options.colorspace || options.colourspace)
+    case 'toColorspace':
+    case 'toColourspace':
+      return pipeline.toColorspace(options.colorspace || options.colourspace)
+    case 'ensureAlpha':
+      return pipeline.ensureAlpha(options.alpha)
+    case 'extractChannel':
+      return pipeline.extractChannel(options.channel)
+    default:
+      throw new Error(`Unsupported operation ${name}`)
+  }
+}
+
+export function buildPipeline(options: TransformQueryBase) {
+  let pipeline = sharp()
+  if (options.resize) {
+    pipeline = pipeline.resize({
+      fit: options.resize,
+      width: options.width,
+      height: options.height,
+    })
+  }
+  if (options.format) {
+    pipeline = pipeline.toFormat(options.format.name, options.format.options)
+  }
+
+  for (const op of options.op) {
+    try {
+      pipeline = applyOperation(pipeline, op)
+    } catch (e) {
+      throw new Error(`${op.name} is not a valid operation: ${e}`)
+    }
+  }
+  return pipeline
+}
+
+export async function transform(options: TransformQueryBase): Promise<NodeJS.ReadableStream> {
+  const source = await getImage(options.url)
+  const pipeline = buildPipeline(options)
+  const writer = await storage.writeStream(options.hash)
+  const out = new PassThrough()
+  splitter(source.pipe(pipeline), writer, out)
+  return out
+}

src/utils/caniuse.ts

@@ -0,0 +1,50 @@
+import DeviceDetector from 'device-detector-js'
+import Avif from 'caniuse-db/features-json/avif.json'
+import WebP from 'caniuse-db/features-json/webp.json'
+
+const detector = new DeviceDetector()
+
+function findLowestCompatibleVersion(stat: Record<string, string>): string {
+  const entries = Object.entries(stat).sort((a, b) => parseInt(a[0]) - parseInt(b[0]))
+  for (const [version, support] of entries) {
+    if (support.startsWith('y') || support.startsWith('a')) {
+      return version
+    }
+  }
+}
+
+const mapping = {
+  'Internet Explorer': 'ie',
+  'Microsoft Edge': 'edge',
+  Firefox: 'firefox',
+  Chrome: 'chrome',
+  Safari: 'safari',
+  Opera: 'opera',
+  'Mobile Safari': 'ios_saf',
+  'Opera Mini': 'op_mini',
+  'Android Browser': 'android',
+  'Chrome Mobile': 'and_chr',
+  'Firefox Mobile': 'and_ff',
+  'UC Browser': 'and_uc',
+  'Samsung Browser': 'samsung',
+  'QQ Browser': 'and_qq',
+}
+
+function matchBrowserToStat(browser: DeviceDetector.DeviceDetectorResult): string {
+  if (!browser.os || !browser.client) throw new Error('Invalid browser')
+  if (browser.os.name === 'iOS') {
+    return 'ios_saf'
+  }
+  if (browser.os.name in mapping) {
+    return mapping[browser.os.name as keyof typeof mapping]
+  }
+  throw new Error('Could not determine mapping for browser')
+}
+
+function match(feature: typeof Avif | typeof WebP, ua: string): boolean {
+  const browser = detector.parse(ua)
+  const stats = feature.stats[matchBrowserToStat(browser) as keyof typeof feature.stats]
+  console.debug(stats)
+  console.debug(findLowestCompatibleVersion(stats))
+  return false
+}

src/utils/utils.ts

@@ -0,0 +1,39 @@
+import { createHash } from 'crypto'
+import { validateSync, ValidatorOptions, ValidationError as VE } from 'class-validator'
+import { PassThrough, Readable } from 'stream'
+
+export class ValidationError extends Error {
+  override message: string
+
+  constructor(errors: VE[]) {
+    super()
+    this.message = errors
+      .map((e) => Object.values(e.constraints!))
+      .flat()
+      .join(', ')
+  }
+}
+
+export function validateSyncOrFail(data: object, options: ValidatorOptions = {}) {
+  options = Object.assign({ whitelist: true, forbidUnknownValues: true, skipMissingProperties: false }, options)
+  const errors = validateSync(data, options)
+  if (errors.length > 0) {
+    throw new ValidationError(errors)
+  }
+}
+
+export function sha3(url: string) {
+  return createHash('sha3-256').update(url).digest('hex')
+}
+
+export function sortObjectByKeys<T extends object>(obj: T): T {
+  return Object.fromEntries(Object.entries(obj).sort((a, b) => a[0].localeCompare(b[0]))) as T
+}
+
+export function splitter(from: NodeJS.ReadableStream, ...streams: NodeJS.WritableStream[]) {
+  const splitter = new PassThrough()
+  for (const stream of streams) {
+    splitter.pipe(stream)
+  }
+  from.pipe(splitter)
+}

tsconfig.json

@@ -0,0 +1,100 @@
+{
+  "compilerOptions": {
+    /* Visit https://aka.ms/tsconfig.json to read more about this file */
+
+    /* Projects */
+    "incremental": true /* Enable incremental compilation */,
+    "composite": true /* Enable constraints that allow a TypeScript project to be used with project references. */,
+    // "tsBuildInfoFile": "./",                          /* Specify the folder for .tsbuildinfo incremental compilation files. */
+    // "disableSourceOfProjectReferenceRedirect": true,  /* Disable preferring source files instead of declaration files when referencing composite projects */
+    // "disableSolutionSearching": true,                 /* Opt a project out of multi-project reference checking when editing. */
+    // "disableReferencedProjectLoad": true,             /* Reduce the number of projects loaded automatically by TypeScript. */
+
+    /* Language and Environment */
+    "target": "es2021" /* Set the JavaScript language version for emitted JavaScript and include compatible library declarations. */,
+    // "lib": [],                                        /* Specify a set of bundled library declaration files that describe the target runtime environment. */
+    // "jsx": "preserve",                                /* Specify what JSX code is generated. */
+    "experimentalDecorators": true /* Enable experimental support for TC39 stage 2 draft decorators. */,
+    "emitDecoratorMetadata": true /* Emit design-type metadata for decorated declarations in source files. */,
+    // "jsxFactory": "",                                 /* Specify the JSX factory function used when targeting React JSX emit, e.g. 'React.createElement' or 'h' */
+    // "jsxFragmentFactory": "",                         /* Specify the JSX Fragment reference used for fragments when targeting React JSX emit e.g. 'React.Fragment' or 'Fragment'. */
+    // "jsxImportSource": "",                            /* Specify module specifier used to import the JSX factory functions when using `jsx: react-jsx*`.` */
+    // "reactNamespace": "",                             /* Specify the object invoked for `createElement`. This only applies when targeting `react` JSX emit. */
+    // "noLib": true,                                    /* Disable including any library files, including the default lib.d.ts. */
+    // "useDefineForClassFields": true,                  /* Emit ECMAScript-standard-compliant class fields. */
+
+    /* Modules */
+    "module": "commonjs" /* Specify what module code is generated. */,
+    "rootDir": "./src" /* Specify the root folder within your source files. */,
+    // "moduleResolution": "node",                       /* Specify how TypeScript looks up a file from a given module specifier. */
+    // "baseUrl": "./",                                  /* Specify the base directory to resolve non-relative module names. */
+    // "paths": {},                                      /* Specify a set of entries that re-map imports to additional lookup locations. */
+    // "rootDirs": [],                                   /* Allow multiple folders to be treated as one when resolving modules. */
+    // "typeRoots": [],                                  /* Specify multiple folders that act like `./node_modules/@types`. */
+    // "types": [],                                      /* Specify type package names to be included without being referenced in a source file. */
+    // "allowUmdGlobalAccess": true,                     /* Allow accessing UMD globals from modules. */
+    "resolveJsonModule": true /* Enable importing .json files */,
+    // "noResolve": true,                                /* Disallow `import`s, `require`s or `<reference>`s from expanding the number of files TypeScript should add to a project. */
+
+    /* JavaScript Support */
+    // "allowJs": true,                                  /* Allow JavaScript files to be a part of your program. Use the `checkJS` option to get errors from these files. */
+    // "checkJs": true,                                  /* Enable error reporting in type-checked JavaScript files. */
+    // "maxNodeModuleJsDepth": 1,                        /* Specify the maximum folder depth used for checking JavaScript files from `node_modules`. Only applicable with `allowJs`. */
+
+    /* Emit */
+    "declaration": true /* Generate .d.ts files from TypeScript and JavaScript files in your project. */,
+    "declarationMap": true /* Create sourcemaps for d.ts files. */,
+    // "emitDeclarationOnly": true,                      /* Only output d.ts files and not JavaScript files. */
+    "sourceMap": true /* Create source map files for emitted JavaScript files. */,
+    // "outFile": "./",                                  /* Specify a file that bundles all outputs into one JavaScript file. If `declaration` is true, also designates a file that bundles all .d.ts output. */
+    "outDir": "./dist" /* Specify an output folder for all emitted files. */,
+    // "removeComments": true,                           /* Disable emitting comments. */
+    // "noEmit": true,                                   /* Disable emitting files from a compilation. */
+    // "importHelpers": true,                            /* Allow importing helper functions from tslib once per project, instead of including them per-file. */
+    // "importsNotUsedAsValues": "remove",               /* Specify emit/checking behavior for imports that are only used for types */
+    // "downlevelIteration": true,                       /* Emit more compliant, but verbose and less performant JavaScript for iteration. */
+    // "sourceRoot": "",                                 /* Specify the root path for debuggers to find the reference source code. */
+    // "mapRoot": "",                                    /* Specify the location where debugger should locate map files instead of generated locations. */
+    // "inlineSourceMap": true,                          /* Include sourcemap files inside the emitted JavaScript. */
+    // "inlineSources": true,                            /* Include source code in the sourcemaps inside the emitted JavaScript. */
+    // "emitBOM": true,                                  /* Emit a UTF-8 Byte Order Mark (BOM) in the beginning of output files. */
+    // "newLine": "crlf",                                /* Set the newline character for emitting files. */
+    // "stripInternal": true,                            /* Disable emitting declarations that have `@internal` in their JSDoc comments. */
+    // "noEmitHelpers": true,                            /* Disable generating custom helper functions like `__extends` in compiled output. */
+    // "noEmitOnError": true,                            /* Disable emitting files if any type checking errors are reported. */
+    // "preserveConstEnums": true,                       /* Disable erasing `const enum` declarations in generated code. */
+    // "declarationDir": "./",                           /* Specify the output directory for generated declaration files. */
+
+    /* Interop Constraints */
+    // "isolatedModules": true,                          /* Ensure that each file can be safely transpiled without relying on other imports. */
+    // "allowSyntheticDefaultImports": true,             /* Allow 'import x from y' when a module doesn't have a default export. */
+    "esModuleInterop": true /* Emit additional JavaScript to ease support for importing CommonJS modules. This enables `allowSyntheticDefaultImports` for type compatibility. */,
+    // "preserveSymlinks": true,                         /* Disable resolving symlinks to their realpath. This correlates to the same flag in node. */
+    "forceConsistentCasingInFileNames": true /* Ensure that casing is correct in imports. */,
+
+    /* Type Checking */
+    "strict": true /* Enable all strict type-checking options. */,
+    "noImplicitAny": true /* Enable error reporting for expressions and declarations with an implied `any` type.. */,
+    "strictNullChecks": true /* When type checking, take into account `null` and `undefined`. */,
+    "strictFunctionTypes": true /* When assigning functions, check to ensure parameters and the return values are subtype-compatible. */,
+    "strictBindCallApply": true /* Check that the arguments for `bind`, `call`, and `apply` methods match the original function. */,
+    "strictPropertyInitialization": true /* Check for class properties that are declared but not set in the constructor. */,
+    "noImplicitThis": true /* Enable error reporting when `this` is given the type `any`. */,
+    "useUnknownInCatchVariables": true /* Type catch clause variables as 'unknown' instead of 'any'. */,
+    "alwaysStrict": true /* Ensure 'use strict' is always emitted. */,
+    // "noUnusedLocals": true,                           /* Enable error reporting when a local variables aren't read. */
+    // "noUnusedParameters": true,                       /* Raise an error when a function parameter isn't read */
+    // "exactOptionalPropertyTypes": true /* Interpret optional property types as written, rather than adding 'undefined'. */,
+    "noImplicitReturns": true /* Enable error reporting for codepaths that do not explicitly return in a function. */,
+    "noFallthroughCasesInSwitch": true /* Enable error reporting for fallthrough cases in switch statements. */,
+    "noUncheckedIndexedAccess": true /* Include 'undefined' in index signature results */,
+    "noImplicitOverride": true /* Ensure overriding members in derived classes are marked with an override modifier. */,
+    "noPropertyAccessFromIndexSignature": true /* Enforces using indexed accessors for keys declared using an indexed type */,
+    "allowUnusedLabels": true /* Disable error reporting for unused labels. */,
+    "allowUnreachableCode": true /* Disable error reporting for unreachable code. */,
+
+    /* Completeness */
+    // "skipDefaultLibCheck": true,                      /* Skip type checking .d.ts files that are included with TypeScript. */
+    "skipLibCheck": true /* Skip type checking all .d.ts files. */
+  }
+}