Add types to events-handler, add test and prettier with eslint

.babelrc

@@ -0,0 +1,46 @@
+{
+	"presets": [
+		[
+			"@babel/preset-env",
+			{
+				"targets": {
+					"browsers": "last 2 versions"
+				}
+			}
+		],
+		"@babel/typescript"
+	],
+	"plugins": [
+		[
+			"@babel/plugin-proposal-decorators",
+			{
+				"legacy": true
+			}
+		],
+		"@babel/plugin-syntax-dynamic-import",
+		"@babel/plugin-syntax-import-meta",
+		[
+			"@babel/plugin-proposal-class-properties",
+			{
+				"loose": true
+			}
+		],
+		"@babel/plugin-proposal-json-strings",
+		"@babel/plugin-proposal-function-sent",
+		"@babel/plugin-proposal-export-namespace-from",
+		"@babel/plugin-proposal-numeric-separator",
+		"@babel/plugin-proposal-throw-expressions",
+		"@babel/plugin-proposal-export-default-from",
+		"@babel/plugin-proposal-logical-assignment-operators",
+		"@babel/plugin-proposal-optional-chaining",
+		[
+			"@babel/plugin-proposal-pipeline-operator",
+			{
+				"proposal": "minimal"
+			}
+		],
+		"@babel/plugin-proposal-nullish-coalescing-operator",
+		"@babel/plugin-proposal-do-expressions",
+		"@babel/plugin-proposal-function-bind"
+	]
+}

.eslintrc.js

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+module.exports = {
+  parser: '@typescript-eslint/parser', // Specifies the ESLint parser
+  extends: [
+    'plugin:@typescript-eslint/recommended', // Uses the recommended rules from @typescript-eslint/eslint-plugin
+    'plugin:prettier/recommended', // Enables eslint-plugin-prettier and displays prettier errors as ESLint errors. Make sure this is always the last configuration in the extends array.
+  ],
+  parserOptions: {
+    ecmaVersion: 2019, // Allows for the parsing of modern ECMAScript features
+    sourceType: 'module', // Allows for the use of imports
+    ecmaFeatures: {
+      jsx: false, // Allows for the parsing of JSX
+    },
+  },
+  rules: {
+    // Place to specify ESLint rules. Can be used to overwrite rules specified from the extended configs
+    '@typescript-eslint/no-explicit-any': 'off',
+  },
+};

.prettierrc

@@ -0,0 +1,7 @@
+{
+    "useTabs": false,
+    "printWidth": 100,
+    "singleQuote": true,
+    "trailingComma": "es5",
+    "semi": true
+}

jest.config.js

@@ -0,0 +1,12 @@
+module.exports = {
+  preset: 'ts-jest',
+  verbose: true,
+  name: 'ccc',
+  moduleFileExtensions: ['js', 'ts'],
+  transformIgnorePatterns: ['<rootDir>/node_modules/'],
+  coverageDirectory: './coverage/',
+  coverageReporters: ['json-summary', 'text', 'lcov'],
+  collectCoverage: true,
+  roots: ['<rootDir>/src'],
+  setupFiles: ['<rootDir>/setupTests.js'],
+};