chore(dep): update jest to v24.x (#146)

* chore(dep): update jest to v24.x

* chore: add "preset": "ts-jest"

Documentation: https://kulshekhar.github.io/ts-jest/user/config/#jest-preset

* fix: add @types/node@^10.14.19

This fixes "error TS2304: Cannot find name 'Set'"
Refs: DefinitelyTyped/DefinitelyTyped#29172

* fix: 'undefined' is not assignable 'string'

package.json

@@ -43,14 +43,14 @@
     "yargs": "^11.0.0"
   },
   "devDependencies": {
-    "@types/jest": "^23.1.0",
-    "@types/node": "^7.0.22",
+    "@types/jest": "^24.0.18",
+    "@types/node": "^10.14.19",
     "fs-extra": "^6.0.1",
-    "jest": "^23.1.0",
+    "jest": "^24.9.0",
     "jest-runner-tslint": "^1.0.5",
     "prettier": "1.13.5",
     "rimraf": "^2.6.2",
-    "ts-jest": "^22.4.6",
+    "ts-jest": "^24.1.0",
     "tslint": "^5.10.0",
     "tslint-config-prettier": "^1.13.0",
     "tslint-plugin-prettier": "^1.3.0",
@@ -77,17 +77,7 @@
         "roots": [
           "src"
         ],
-        "transform": {
-          "^.+\\.jsx?$": "<rootDir>/node_modules/ts-jest/preprocessor.js",
-          "^.+\\.tsx?$": "<rootDir>/node_modules/ts-jest/preprocessor.js"
-        },
-        "testRegex": "(/__tests__/.*|\\.(test|spec))\\.(ts|tsx|js)$",
-        "moduleFileExtensions": [
-          "ts",
-          "tsx",
-          "js",
-          "json"
-        ]
+        "preset": "ts-jest"
       },
       {
         "runner": "jest-runner-tslint",

src/github-api.ts

@@ -65,6 +65,6 @@ export default class GithubAPI {
   }
 
   private getAuthToken(): string {
-    return process.env.GITHUB_AUTH;
+    return process.env.GITHUB_AUTH || "";
   }
 }