fix: add tslint

package.json

@@ -4,14 +4,17 @@
   "description": "",
   "main": "build/src/index.js",
   "scripts": {
-    "test": "jest --coverage"
+    "build": "tsc",
+    "lint": "tslint --fix -p .",
+    "test": "npm run lint && jest --coverage"
   },
   "author": "",
   "license": "Apache-2.0",
   "devDependencies": {
     "@types/jest": "^24.0.13",
     "jest": "^24.8.0",
     "ts-jest": "^24.0.2",
+    "tslint": "^5.17.0",
     "typescript": "^3.5.1"
   }
 }

src/index.test.ts

@@ -1,8 +1,7 @@
 import helloWorld from "./index";
 
-
 describe("index", () => {
   it("can call hello world", () => {
     expect(helloWorld()).toEqual("hello world");
-  })
-})
+  });
+});

src/index.ts

@@ -1,4 +1,5 @@
 export function helloWorld() {
+  // hello world
   return "hello world";
 }
 

tsconfig.json

@@ -1,7 +1,7 @@
 {
   "compilerOptions": {
     "target": "es5",
-    "module": "esnext",
+    "module": "commonjs",
     "lib": [
       "es2015",
       "dom"

tslint.json

@@ -0,0 +1,12 @@
+{
+  "extends": [
+    "tslint:recommended"
+  ],
+  "rules": {
+    "ordered-imports": false,
+    "object-literal-sort-keys": false,
+    "no-console": [true, "log"],
+    "indent": [true, "spaces", 2],
+    "max-classes-per-file" : false
+  }
+}