upgrade dev tooling setup

- force `git` to keep original line-endings (tests fail otherwise)

- pin `@types/node` to v8 (was: v10)
- update `eslint` and plugins
- update `typescript`, `tslib`, `ts-node`

- add typescript's native typechecking as `typecheck` npm script
- add `typescript-eslint` and enable linting in ts files

- remove redundant eslint rules
- add `eol-last`, `no-trailing-spaces` and `dot-notation` rules

`eslint`, `prettier` and `editorconfig` settings used to conflict
with each other, so I aligned them (where possible) to the `eslint`
rules

TODO: fix all linting errors in typescript
TODO: refactor typescript interfaces to make compilation type-safe

.editorconfig

@@ -1,16 +1,12 @@
 root = true
 
 [*]
+charset = utf-8
 end_of_line = lf
-insert_final_newline = true
-indent_style = tab
 indent_size = 2
-charset = utf-8
-trim_trailing_whitespace = true
-
-[test/**/expected.css]
+indent_style = tab
 insert_final_newline = false
+trim_trailing_whitespace = true
 
-[{package.json,.travis.yml,.eslintrc.json}]
-indent_style = space
-indent_size = 2
+[.travis.yml]
+indent_style = space

.eslintrc.js

@@ -0,0 +1,52 @@
+module.exports = {
+	root: true,
+
+	rules: {
+		// automatically fixable stylistic rules
+		'arrow-spacing': 2,
+		'comma-dangle': [2, 'never'],
+		'dot-notation': 2,
+		'eol-last': [2, 'never'],
+		indent: [2, 'tab', { SwitchCase: 1 }],
+		'keyword-spacing': [2, { before: true, after: true }],
+		'no-trailing-spaces': 2,
+		'no-var': 2,
+		'object-shorthand': [2, 'always'],
+		'one-var': [2, 'never'],
+		'prefer-arrow-callback': 2,
+		'prefer-const': [2, { destructuring: 'all' }],
+		'quote-props': [2, 'as-needed'],
+		semi: [2, 'always'],
+		'space-before-blocks': [2, 'always'],
+
+		// eslint:recommended overrides
+		'no-cond-assign': 0,
+		'no-inner-declarations': 0,
+		'no-mixed-spaces-and-tabs': [2, 'smart-tabs']
+	},
+
+	plugins: ['@typescript-eslint'],
+
+	extends: [
+		'eslint:recommended',
+		'plugin:import/errors',
+		'plugin:import/warnings',
+		'plugin:import/typescript'
+		// TODO: fix typerscript files
+		// 'plugin:@typescript-eslint/recommended',
+	],
+
+	parser: '@typescript-eslint/parser',
+	parserOptions: {
+		ecmaVersion: 9,
+		sourceType: 'module',
+		project: './tsconfig.json'
+	},
+
+	env: {
+		es6: true,
+		browser: true,
+		node: true,
+		mocha: true
+	}
+};

.gitattributes

@@ -1 +1,2 @@
-*.svelte linguist-language=HTML
+* text=auto eol=lf
+*.svelte linguist-language=HTML

.prettierrc.js

@@ -0,0 +1,9 @@
+module.exports = {
+	arrowParens: 'avoid',
+	endOfLine: 'lf',
+	quoteProps: 'as-needed',
+	semi: true,
+	singleQuote: true,
+	trailingComma: 'none',
+	useTabs: true
+};