完成作业

.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
+    # 运行测试
+    - run: yarn test

lib/add.js

@@ -1,5 +1,21 @@
-function add() {
+function add(num1, num2) {
   // 实现该函数
+  // 利用BigInt
+  // return String(BigInt(num1) + BigInt(num2))
+  // 字符串截取进位
+  const safeLength = 14;
+  let a = num1;
+  let b = num2; // 保留一份参数值
+  let flag = 0, // 进位标识
+      res = ''; // 结果
+  while(a.length || b.length || flag) {
+    const andSum = String(parseInt(a.substr(-safeLength) || 0, 10) + parseInt(b.substr(-safeLength) || 0, 10));
+    res = parseInt(andSum.substr(-safeLength) || 0, 10) + flag + res;
+    flag = andSum.length > safeLength;
+    a = a.substr(0, a.length - safeLength);
+    b = b.substr(0, b.length - safeLength);
+  }
+  return res
 }
 
 module.exports = add