feat: add ts typedefs (#32)

* feat: add ts typedefs

* fix: address review comments

* feat: add type checking to CI

* Update index.d.ts

Co-authored-by: Alex Potsides <[email protected]>

* Update .github/workflows/typecheck.yml

Co-authored-by: Alex Potsides <[email protected]>

.github/workflows/typecheck.yml

@@ -0,0 +1,28 @@
+on:
+  pull_request:
+    branches:
+      - '*'
+
+name: Typecheck
+jobs:
+  check:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        node-version: [14.x]
+    steps:
+      - uses: actions/checkout@v2
+      - name: Use Node.js ${{ matrix.node-version }}
+        uses: actions/setup-node@v1
+        with:
+          node-version: ${{ matrix.node-version }}
+      - name: Restore dependencies
+        id: cache-modules
+        uses: actions/checkout@v2
+        with:
+          path: node_modules
+          key: ${{ matrix.node-version }}-${{ runner.OS }}-build-${{ hashFiles('package.json') }}
+      - name: Install dependencies
+        run: npm install
+      - name: Typecheck
+        uses: gozala/[email protected]

.gitignore

@@ -1,2 +1,3 @@
 node_modules
 npm-debug.*
+*.tsbuildinfo

index.d.ts

@@ -0,0 +1,16 @@
+interface Err<Code> extends Error {
+  code: Code
+}
+
+interface CreateError {
+  <Code extends string|number, Ext extends Object> (
+    error:Error,
+    code: Code,
+    ext: Ext
+  ): Err<Code> & Ext
+  <Code extends string|number> (error:Error, code:Code): Err<Code>
+  <Ext extends Object> (error:Error, ext:Ext): Err<undefined> & Ext
+}
+
+declare var createError:CreateError
+export = createError