diff --git a/.github/workflows/node.js.yml b/.github/workflows/node.js.yml
new file mode 100644
index 0000000..54857db
--- /dev/null
+++ b/.github/workflows/node.js.yml
@@ -0,0 +1,30 @@
+# This workflow will do a clean installation of node dependencies, cache/restore them, build the source code and run tests across different versions of node
+# For more information see: https://help.github.com/actions/language-and-framework-guides/using-nodejs-with-github-actions
+
+name: Node.js CI
+
+on:
+  push:
+    branches: [ "master" ]
+  pull_request:
+    branches: [ "master" ]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        node-version: [16.x]
+        # See supported Node.js release schedule at https://nodejs.org/en/about/releases/
+
+    steps:
+    - uses: actions/checkout@v3
+    - name: Use Node.js ${{ matrix.node-version }}
+      uses: actions/setup-node@v3
+      with:
+        node-version: ${{ matrix.node-version }}
+    - run: yarn
+    # Just run tests once
+    - run: yarn test
diff --git a/lib/add.js b/lib/add.js
index 1714b95..3998c08 100644
--- a/lib/add.js
+++ b/lib/add.js
@@ -1,5 +1,22 @@
-function add() {
-  // 实现该函数
+function add(num1, num2) {
+    // 强转字符串，对于输入参数值为Number类型的正整数也可以支持
+
+    num1 = String(num1);
+    num2 = String(num2);
+    let lenMax = num1.length > num2.length ? num1.length : num2.length;
+    num1 = num1.padStart(lenMax, '0');
+    num2 = num2.padStart(lenMax, '0');
+    let carry = 0;
+    let result = '';
+    for (let i = lenMax - 1; i >= 0; i--) {
+        let sum = parseInt(num1[i]) + parseInt(num2[i]) + carry;
+        result = sum % 10 + result;
+        carry = sum > 9 ? 1 : 0;
+    }
+    if (carry === 1) {
+        result = 1 + result;
+    }
+    return result;
 }
 
 module.exports = add
\ No newline at end of file