Migrate codebase to TypeScript, upgrade dependencies

Author: ivome

.circleci/config.yml

@@ -7,7 +7,7 @@ jobs:
   build:
     docker:
       # specify the version you desire here
-      - image: circleci/node:7.10
+      - image: circleci/node:latest
 
     working_directory: ~/repo
 
@@ -21,12 +21,12 @@ jobs:
           # fallback to using the latest cache if no exact match is found
           - v1-dependencies-
 
-      - run: npm install
+      - run: yarn
 
       - save_cache:
           paths:
             - node_modules
           key: v1-dependencies-{{ checksum "package.json" }}
 
       # run tests!
-      - run: npm test
+      - run: yarn test

.eslintrc

@@ -1,15 +1,12 @@
 {
-    "parser": "babel-eslint",
+    "parser": "typescript-eslint-parser",
 
     "plugins": [
-        "babel",
-        "flowtype",
-        "flowtype-errors"
+        "typescript"
     ],
 
     "extends": [
-        "eslint:recommended",
-        "plugin:flowtype/recommended"
+        "eslint:recommended"
     ],
 
     "env": {
@@ -58,7 +55,6 @@
     },
 
     "rules": {
-        "flowtype-errors/show-errors": 2,
         "arrow-parens": [2, "as-needed"],
         "array-bracket-spacing": [2, "always"],
         "generator-star-spacing": [2, {"before": true, "after": false}],