Use tsc (#262)

* rename files to .ts, update to use es6 imports/exports, and build and watch scripts

* add babel submodule, use .ts for test files, update jest configuration

* install babel deps

* get playground working again

* upgrade jest and fix coverage reporting

* add 'prepublishOnly' script and 'files' section to package.json

* build cli as well as convert

* update 'dev quick start' in README

Author: kevinbarabash

.circleci/config.yml

@@ -12,7 +12,12 @@ jobs:
         uses: actions/setup-node@v1
         with:
           node-version: 12.x
-      - name: yarn install
+      - name: checkout babel submodule
+        run: git submodule update --depth 1 --init -- babel
+      - name: install babel deps
+        working-directory: ./babel
+        run: yarn install
+      - name: install flow-to-ts deps
         run: yarn install
       - name: yarn coverage
         run: yarn coverage
@@ -34,7 +39,12 @@ jobs:
         uses: actions/setup-node@v1
         with:
           node-version: ${{ matrix.node-version }}
-      - name: yarn install
+      - name: checkout babel submodule
+        run: git submodule update --depth 1 --init -- babel
+      - name: install babel deps
+        working-directory: ./babel
+        run: yarn install
+      - name: install flow-to-ts deps
         run: yarn install
       - name: yarn test
         run: yarn test

.github/workflows/node.yml

@@ -1,3 +1,4 @@
 node_modules
 coverage
 docs
+dist

.gitignore

@@ -0,0 +1,3 @@
+[submodule "babel"]
+	path = babel
+	url = https://github.com/kevinbarabash/babel

.gitmodules

@@ -61,6 +61,10 @@ test cases and should have 100% diff coverage.
 ```bash
 git clone [email protected]:Khan/flow-to-ts.git
 cd flow-to-ts
+git submodule update --depth 1 --init -- babel
+cd babel
+yarn
+cd ..
 yarn
 yarn test
 ```