feat: update dependencies and add TS definition

.github/workflows/nodejs.yml

@@ -0,0 +1,40 @@
+name: Node.js CI
+
+on:
+  push:
+    branches: master
+  pull_request:
+
+env:
+  NODE_VERSION: 14.x
+
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-node@v2
+        with:
+          node-version: ${{ env.NODE_VERSION }}
+      - name: Install dependencies
+        run: npm install
+      - name: Run ESLint
+        run: npm run eslint
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        node-version: [12.x, 14.x, 16.x]
+      fail-fast: false
+    steps:
+      - uses: actions/checkout@v2
+      - name: Use Node.js ${{ matrix.node-version }}
+        uses: actions/setup-node@v2
+        with:
+          node-version: ${{ matrix.node-version }}
+      - name: Install dependencies
+        run: npm install
+      - name: Run tests
+        run: npm run test-coverage
+      - name: Send coverage report to Codecov
+        uses: codecov/codecov-action@v1

.npmrc

@@ -0,0 +1 @@
+package-lock=false

.prettierrc.json

@@ -0,0 +1,7 @@
+{
+  "arrowParens": "always",
+  "semi": true,
+  "singleQuote": true,
+  "tabWidth": 2,
+  "trailingComma": "all"
+}

README.md

@@ -1,7 +1,7 @@
 # regression-exponential
 
 [![NPM version][npm-image]][npm-url]
-[![build status][travis-image]][travis-url]
+[![build status][ci-image]][ci-url]
 [![npm download][download-image]][download-url]
 
 Exponential Regression.
@@ -32,9 +32,9 @@ regression.toString(3); // f(x) = 1.58 * exp(0.391 * x)
 
 [MIT](./LICENSE)
 
-[npm-image]: https://img.shields.io/npm/v/ml-regression-exponential.svg?style=flat-square
+[npm-image]: https://img.shields.io/npm/v/ml-regression-exponential.svg
 [npm-url]: https://npmjs.org/package/ml-regression-exponential
-[travis-image]: https://img.shields.io/travis/mljs/regression-exponential/master.svg?style=flat-square
-[travis-url]: https://travis-ci.org/mljs/regression-exponential
-[download-image]: https://img.shields.io/npm/dm/ml-regression-exponential.svg?style=flat-square
+[ci-image]: https://github.com/mljs/regression-exponential/workflows/Node.js%20CI/badge.svg?branch=master
+[ci-url]: https://github.com/mljs/regression-exponential/actions?query=workflow%3A%22Node.js+CI%22
+[download-image]: https://img.shields.io/npm/dm/ml-regression-exponential.svg
 [download-url]: https://npmjs.org/package/ml-regression-exponential