feat: rewrite to TypeScript … (#202)

BREAKING CHANGE: Drop Flow, bump minimum Node version to 12.

Co-authored-by: Matthew Fernando Garcia <[email protected]>

.babelrc.js

@@ -1,16 +1,13 @@
 module.exports = {
-  plugins: [
-    '@babel/proposal-nullish-coalescing-operator',
-    '@babel/proposal-optional-chaining',
-  ],
+  plugins: ['@babel/proposal-nullish-coalescing-operator'],
   presets: [
     [
       '@babel/env',
       {
         modules: process.env.NODE_ENV === 'test' && 'commonjs',
-        targets: {node: '6'},
+        targets: {node: '12'},
       },
     ],
-    '@babel/flow',
+    '@babel/typescript',
   ],
 };

.circleci/config.yml

@@ -1,7 +1,7 @@
 jobs:
   lint:
     docker:
-      - image: circleci/node:8
+      - image: circleci/node:12
     steps:
       - checkout
       - restore_cache:
@@ -18,7 +18,7 @@ jobs:
 
   release:
     docker:
-      - image: circleci/node:8
+      - image: circleci/node:12
     steps:
       - checkout
       - restore_cache:
@@ -35,7 +35,7 @@ jobs:
 
   test:
     docker:
-      - image: circleci/node:8
+      - image: circleci/node:12
     steps:
       - checkout
       - restore_cache:
@@ -52,7 +52,7 @@ jobs:
 
   test-dist:
     docker:
-      - image: circleci/node:8
+      - image: circleci/node:12
     steps:
       - checkout
       - restore_cache:

.eslintignore

@@ -1,4 +1,3 @@
 coverage/*
 dist/*
-flow-typed/*
 node_modules/*

.eslintrc.js

@@ -0,0 +1,57 @@
+const rushstackEslintConfig = require('@rushstack/eslint-config/profile/node');
+const assert = require('assert');
+const path = require('path');
+const {isDeepStrictEqual} = require('util');
+
+// Rushstack: "This is a workaround for https://github.com/eslint/eslint/issues/3458".
+require('@rushstack/eslint-config/patch/modern-module-resolution');
+
+// ESLint configuration is not user-friendly.
+const overrides = rushstackEslintConfig.overrides.filter((override) =>
+  isDeepStrictEqual(override.files, ['*.ts', '*.tsx']),
+);
+assert(
+  overrides.length === 1,
+  "The assumption for locating the .ts override in '@rushstack/eslint-config' is faulty.",
+);
+
+module.exports = {
+  extends: [
+    '@rushstack/eslint-config/profile/node',
+    '@rushstack/eslint-config/mixins/tsdoc',
+    'plugin:eslint-comments/recommended',
+    'plugin:unicorn/recommended',
+  ],
+  overrides: [
+    {
+      files: ['types/*.d.ts'],
+      rules: {
+        // Type files should have the name of the packages that use them, which don't necessarily follow this rule (e.g. `JSONStream`).
+        'unicorn/filename-case': 'off',
+      },
+    },
+    {
+      files: ['*.ts'],
+      rules: {
+        '@rushstack/typedef-var': 'off',
+        // Rationale: https://github.com/microsoft/rushstack/blob/63777148e110b2d9b690e60d74e58af03d0e7b7e/stack/eslint-config/index.js#L327-L332
+        '@typescript-eslint/naming-convention': overrides[0].rules[
+          '@typescript-eslint/naming-convention'
+        ].map((value) =>
+          typeof value === 'object' && value.selector === 'interface'
+            ? {format: ['PascalCase'], selector: 'interface'}
+            : value,
+        ),
+      },
+    },
+  ],
+  parserOptions: {
+    project: path.join(__dirname, './tsconfig.json'),
+  },
+  rules: {
+    'eslint-comments/no-unused-disable': 'error',
+    // Since this is covered by 'eslint-comments/no-unlimited-disable'.
+    'unicorn/no-abusive-eslint-disable': 'off',
+    'unicorn/no-unsafe-regex': 'error',
+  },
+};

.gitignore

@@ -1,7 +1,5 @@
 coverage
 dist
-lib
 node_modules
 yarn.lock
-yarn-debug.log*
-yarn-error.log*
+*.log*

.huskyrc.yaml

@@ -0,0 +1,3 @@
+hooks:
+  commit-msg: commitlint -e $HUSKY_GIT_PARAMS
+  pre-commit: tsc && cross-env NODE_ENV=test lint-staged

.lintstagedrc.yaml

@@ -0,0 +1,6 @@
+'*.{json,md,yaml}':
+  - 'prettier --write'
+'*.{js,ts}':
+  - 'prettier --write'
+  - 'eslint --fix'
+  - 'jest --config ./scripts/jest/config.source.js --bail --findRelatedTests'

README.md

@@ -21,35 +21,24 @@ $ yarn add env-and-files
 ```js
 const {loadConfig} = require('env-and-files');
 
-loadConfig({
-  // A conceptual grouping of configuration properties.  In this case, configuration for the logger.
-  logger: {
-    // The "logger.level" property will be equal to the "LOG_LEVEL" environmental variable, or undefined if it is not present.
-    level: 'LOG_LEVEL',
+loadConfigSync({
+  postgresPassword: {
+    filePath: '/secrets/password',
   },
-  server: {
-    port: {
-      // Specify that this property is required.  If "PORT" is not found, an error will be given.
-      required: true,
-      // Coerce the value to a number.  If it can't be coerced, an error will be given.
-      type: 'number',
-      variableName: 'PORT',
-    },
+  postgresUrl: {
+    format: (value) => new URL(value),
+    variableName: 'POSTGRES_URL',
   },
-  sql: {
-    password: {
-      // The "sql.password" property will be equal to the contents of "/path/to/secret", or undefined if it could not be read.
-      filePath: '/path/to/secret',
-      required: true,
-    },
+  postgresUsername: {
+    defaultValue: 'postgres',
+    filePath: '/secrets/username',
   },
 })
-  .then(config => {
-    // "config" will be an object map of configuration groups.  So, you'd get something like
-    // { logger: { level: undefined }, server: { port: 8000 }, sql: { password: 'abc123' } }
+  .then((config) => {
+    // "config" will be an object map of configuration properties.
     console.log(config);
   })
-  .catch(error => {
+  .catch((error) => {
     // If any of the required properties cannot be loaded, the Promise will reject.
     console.error(error);
   });
@@ -65,7 +54,7 @@ Load configuration. Returns a `Promise` that will resolve to the loaded configur
 
 Type: `Object`
 
-An object map of conceptual groupings of necessary configuration and where to find it. By default, all configuration properties are optional, but if one is marked required and is not found, an error will be given. See [usage](#usage) for examples of config maps.
+An object map of configuration and where to find it. By default, all configuration properties are required. See [usage](#usage) for examples of config maps.
 
 ### loadConfigSync(configMap)
 

__mocks__/fs.js → __mocks__/fs.ts

@@ -1,41 +1,42 @@
-// @flow
 import mapToMap from 'map-to-map';
 
 let files: Map<string, Buffer> = new Map();
 
-function __setFiles(newFiles: {[path: string]: Buffer}) {
+function _setFiles(newFiles: {[path: string]: Buffer}): void {
   files = mapToMap(newFiles);
 }
 
 // $FlowFixMe
 const readFile = jest.fn(
   (
     path: string,
-    encoding: buffer$Encoding,
-    callback: (error: ?Error, value: ?string) => void,
+    encoding: BufferEncoding,
+    // eslint-disable-next-line @rushstack/no-new-null
+    callback: (error: Error | null, value?: string) => void,
   ) => {
     const file = files.get(path);
     if (file && Buffer.isBuffer(file)) {
       const decodedFile = file.toString(encoding);
+      // eslint-disable-next-line unicorn/no-null
       callback(null, decodedFile);
     } else {
-      const error = new Error();
-      callback(error, null);
+      const error = new Error('File not found.');
+      callback(error);
     }
   },
 );
 
 // $FlowFixMe
-const readFileSync = jest.fn((path: string, encoding: buffer$Encoding) => {
+const readFileSync = jest.fn((path: string, encoding: BufferEncoding) => {
   const file = files.get(path);
   if (file && Buffer.isBuffer(file)) {
     return file.toString(encoding);
   }
-  throw new Error();
+  throw new Error('File not found.');
 });
 
 module.exports = {
-  __setFiles,
+  _setFiles,
   readFile,
   readFileSync,
 };