add: sumパッケージの作成と利用

app.js

@@ -1 +1,9 @@
 'use strict';
+
+// モジュールとして取得
+const axios = require('axios');
+
+// HTTPレスポンスを受け取った際に無名関数を渡す
+axios.get('http://www.google.com').then(res => {
+    console.log(res.data);
+});

package.json

@@ -0,0 +1,5 @@
+{
+  "dependencies": {
+    "axios": "^0.22.0"
+  }
+}

sum-app/app.js

@@ -0,0 +1,3 @@
+'use strict';
+const s = require('sum');
+console.log(s.add([1, 2, 3, 4]));

sum-app/package.json

@@ -0,0 +1,9 @@
+{
+  "name": "sum-app",
+  "version": "1.0.0",
+  "main": "index.js",
+  "license": "MIT",
+  "dependencies": {
+    "sum": "../sum"
+  }
+}

sum-app/yarn.lock

@@ -0,0 +1,6 @@
+# THIS IS AN AUTOGENERATED FILE. DO NOT EDIT THIS FILE DIRECTLY.
+# yarn lockfile v1
+
+
+sum@../sum:
+  version "1.0.0"

sum/index.js

@@ -0,0 +1,17 @@
+'use strict';
+
+/**
+ * 数値の配列を受け取って、その要素の合計を返す関数
+ * @param {Number} numbers 数値の配列 
+ * @returns 要素の合計
+ */
+function add(numbers) {
+    let result = 0;
+    for (const num of numbers){
+        result = result + num;
+    }
+    return result;
+}
+
+// 使えるようにしたい関数やオブジェクトを代入する
+module.exports = { add };

sum/package.json

@@ -0,0 +1,6 @@
+{
+  "name": "sum",
+  "version": "1.0.0",
+  "main": "index.js",
+  "license": "MIT"
+}

yarn.lock

@@ -0,0 +1,15 @@
+# THIS IS AN AUTOGENERATED FILE. DO NOT EDIT THIS FILE DIRECTLY.
+# yarn lockfile v1
+
+
+axios@^0.22.0:
+  version "0.22.0"
+  resolved "https://registry.yarnpkg.com/axios/-/axios-0.22.0.tgz#bf702c41fb50fbca4539589d839a077117b79b25"
+  integrity sha512-Z0U3uhqQeg1oNcihswf4ZD57O3NrR1+ZXhxaROaWpDmsDTx7T2HNBV2ulBtie2hwJptu8UvgnJoK+BIqdzh/1w==
+  dependencies:
+    follow-redirects "^1.14.4"
+
+follow-redirects@^1.14.4:
+  version "1.14.4"
+  resolved "https://registry.yarnpkg.com/follow-redirects/-/follow-redirects-1.14.4.tgz#838fdf48a8bbdd79e52ee51fb1c94e3ed98b9379"
+  integrity sha512-zwGkiSXC1MUJG/qmeIFH2HBJx9u0V46QGUe3YR1fXG8bXQxq7fLj0RjLZQ5nubr9qNJUZrH+xUcwXEoXNpfS+g==