Setup eslint with TypeScript configuration

.eslintrc.json

@@ -0,0 +1,37 @@
+{
+	"env": {
+		"es6": true,
+		"jest": true,
+		"node": true
+	},
+	"extends": [
+		"eslint:recommended",
+		"plugin:@typescript-eslint/eslint-recommended",
+		"plugin:@typescript-eslint/recommended",
+		"prettier",
+		"prettier/@typescript-eslint"
+	],
+	"globals": {
+		"Atomics": "readonly",
+		"SharedArrayBuffer": "readonly"
+	},
+	"parser": "@typescript-eslint/parser",
+	"parserOptions": {
+		"project": "./tsconfig.json"
+	},
+	"plugins": ["@typescript-eslint", "prettier"],
+	"rules": {
+		"linebreak-style": ["error", "unix"],
+		"no-case-declarations": "warn",
+		"quotes": ["error", "single", { "avoidEscape": true }],
+		"semi": ["error", "always"],
+
+		"@typescript-eslint/explicit-function-return-type": ["error", { "allowExpressions": true }],
+		"@typescript-eslint/indent": ["error", "tab"],
+		"@typescript-eslint/interface-name-prefix": "off",
+		"@typescript-eslint/no-explicit-any": "off",
+		"@typescript-eslint/no-inferrable-types": "off",
+		"@typescript-eslint/no-parameter-properties": "off",
+		"@typescript-eslint/prefer-string-starts-ends-with": "error"
+	}
+}

.vscode/settings.json

@@ -0,0 +1,3 @@
+{
+	"eslint.validate": ["javascript", "typescript"]
+}

package.json

@@ -5,7 +5,7 @@
 	"main": "dist/index.js",
 	"scripts": {
 		"build": "tsc",
-		"lint": "",
+		"lint": "eslint --ext .ts src",
 		"test": "jest"
 	},
 	"keywords": [
@@ -31,6 +31,11 @@
 		"@types/jest": "~24.0.15",
 		"@types/node": "~12.0.10",
 		"@types/prettier": "~1.16.4",
+		"@typescript-eslint/eslint-plugin": "~1.11.0",
+		"@typescript-eslint/parser": "~1.11.0",
+		"eslint": "~6.0.1",
+		"eslint-config-prettier": "~6.0.0",
+		"eslint-plugin-prettier": "~3.1.0",
 		"jest": "~24.8.0",
 		"ts-jest": "~24.0.2",
 		"typescript": "~3.5.2"

src/index.ts

@@ -77,7 +77,7 @@ export const plugin: Plugin = {
 				let _options: ParserOptions = { ...options };
 				for (const plugin of options.plugins) {
 					if (typeof plugin !== 'string') {
-						if (plugin.parsers && plugin.parsers.hasOwnProperty('pug')) {
+						if (plugin.parsers && Object.prototype.hasOwnProperty.call(plugin.parsers, 'pug')) {
 							_options = { ..._options, ...plugin.defaultOptions, ...plugin.options };
 						}
 					}
@@ -184,7 +184,7 @@ export const plugin: Plugin = {
 							}
 
 							if (previousToken && previousToken.type === 'attribute') {
-								result += `, `;
+								result += ', ';
 							}
 
 							result += `${token.name}`;
@@ -204,11 +204,11 @@ export const plugin: Plugin = {
 									val = val.replace('[ ', '[').replace(' ]', ']');
 									if (quotationType(val) === 'SINGLE') {
 										// Swap single and double quotes
-										val = val.replace(/[\'\"]/g, (match) => (match === '"' ? "'" : '"'));
+										val = val.replace(/['"]/g, (match) => (match === '"' ? "'" : '"'));
 									}
 								} else if (val.startsWith("'")) {
 									// Swap single and double quotes
-									val = val.replace(/[\'\"]/g, (match) => (match === '"' ? "'" : '"'));
+									val = val.replace(/['"]/g, (match) => (match === '"' ? "'" : '"'));
 								} else if (val === 'true') {
 									// The value is exactly true and is not quoted
 									break;
@@ -223,7 +223,7 @@ export const plugin: Plugin = {
 							}
 							break;
 						case 'end-attributes':
-							if (result.charAt(result.length - 1) === '(') {
+							if (result.endsWith('(')) {
 								// There were no attributes
 								result = result.substring(0, result.length - 1);
 							} else if (previousToken && previousToken.type === 'attribute') {
@@ -271,7 +271,7 @@ export const plugin: Plugin = {
 								result = result.substring(0, result.length - 1);
 							}
 							// Insert one newline
-							result += `\n`;
+							result += '\n';
 							break;
 						case 'comment':
 							result += indent.repeat(indentLevel);
@@ -333,7 +333,7 @@ export const plugin: Plugin = {
 								code = code.trim();
 								if (quotationType(code) === 'DOUBLE') {
 									val = '{{ ';
-									val += code.replace(/[\'\"]/g, (match) => (match === '"' ? "'" : '"'));
+									val += code.replace(/['"]/g, (match) => (match === '"' ? "'" : '"'));
 									val += ' }}';
 								}
 							}
@@ -360,7 +360,6 @@ export const plugin: Plugin = {
 							break;
 						case 'id':
 							// Handle id attribute
-							let idVal = token.val;
 							// Write css-id in front of css-classes
 							let lastPositionOfNewline = result.lastIndexOf('\n');
 							if (lastPositionOfNewline === -1) {
@@ -383,7 +382,9 @@ export const plugin: Plugin = {
 										break;
 								}
 							}
-							result = [result.slice(0, position), _indent, `#${idVal}`, result.slice(position)].join('');
+							result = [result.slice(0, position), _indent, `#${token.val}`, result.slice(position)].join(
+								''
+							);
 							break;
 						case 'start-pipeless-text':
 							pipelessText = true;

src/logger.ts

@@ -24,7 +24,7 @@ export class Logger implements ILogger {
 		'error'
 	];
 
-	constructor(private readonly logger: ILogger = console, private level: LogLevel = LogLevel.INFO) {}
+	public constructor(private readonly logger: ILogger = console, private level: LogLevel = LogLevel.INFO) {}
 
 	public setLogLevel(level: LogLevel): void {
 		this.level = level;