Use ts-jest for better coverage

ts-jest module grabs sourceMaps from the compiler so it maps correctly
the ts source code. There is no need to target es6 for coverage anymore.

package.json

@@ -5,6 +5,18 @@
   "main": "src/ReactRouterLinkRenderer.js",
   "author": "Gabriel Aumala",
   "license": "MIT",
+  "jest": {
+    "moduleFileExtensions": [
+      "ts",
+      "tsx",
+      "js"
+    ],
+    "mapCoverage": true,
+    "transform": {
+      "^.+\\.(ts|tsx)$": "ts-jest/preprocessor.js",
+      "^.+\\.jsx?$": "babel-jest"
+    }
+  },
   "peerDependencies": {
     "react": "^15.5.4",
     "react-router-dom": "^4.1.1",
@@ -24,13 +36,14 @@
     "react-router-dom": "^4.1.1",
     "react-test-renderer": "^15.5.4",
     "simple-commonmark-react": "^0.5.0",
+    "ts-jest": "^20.0.5",
     "typescript": "^2.3.4"
   },
   "scripts": {
     "test": "jest --coverage",
     "build": "tsc -d ./src/ReactRouterLinkRenderer.ts",
     "dev": "yarn run build && yarn test",
-    "ci": "yarn run build -- --target es2015 --moduleResolution node && yarn test && cat ./coverage/lcov.info | coveralls",
+    "ci": "yarn run build && yarn test && cat ./coverage/lcov.info | coveralls",
     "release": "yarn run tsc && publish"
   }
 }

src/ReactRouterLinkRenderer.test.js

@@ -3,7 +3,7 @@ import renderer from 'react-test-renderer';
 import { BrowserRouter as Router, Link } from 'react-router-dom'
 import { shallow } from 'enzyme';
 
-import  ReactRouterLinkRenderer from './ReactRouterLinkRenderer.js'
+import  ReactRouterLinkRenderer from './ReactRouterLinkRenderer.ts'
 import { renderNodes } from 'simple-commonmark-react'
 
 const options = { customRenderers: { link: ReactRouterLinkRenderer } }

src/ReactRouterLinkRenderer.ts

@@ -1,6 +1,5 @@
 import { ReactElement, createElement } from 'react'
 import { Link } from 'react-router-dom'
-import { Node } from 'commonmark'
 import LinkRenderer from 'simple-commonmark-react/src/renderers/LinkRenderer'
 
 export default class ReactRouterLinkRender extends LinkRenderer {