20240910 クラス(JavaScript)

04.class/.gitignore

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+db/memo.db

04.class/actions/addMemo.js

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+import { stdin as input } from "process";
+import { createInterface } from "readline";
+
+export async function addMemo(database) {
+  if (process.stdin.isTTY) {
+    console.log(
+      "メモの内容を入力してください（保存するにはCtrl+Dを押してください）:",
+    );
+  }
+
+  let lines;
+  try {
+    lines = await getInputLines(input);
+  } catch (err) {
+    if (err.message === "SIGINT") {
+      console.log("Ctrl+Cが入力された為メモの作成を中止しました");
+      process.exit(1);
+    }
+    if (err.code == "ENOMEM") {
+      throw err;
+    }
+  }
+
+  const isBlank = /^\s*$/.test(lines);
+  if (isBlank) {
+    console.log("メモの内容が空です。");
+    return;
+  }
+
+  try {
+    await database.insert(lines);
+    console.log("メモを追加しました。");
+  } catch (err) {
+    console.error(`メモの保存処理中にエラーが発生しました: "${err.message}`);
+    process.exit(1);
+  }
+}
+
+function getInputLines(input) {
+  return new Promise((resolve, reject) => {
+    const rl = createInterface({
+      input,
+    });
+    const lines = [];
+
+    rl.on("SIGINT", () => {
+      reject(new Error("SIGINT"));
+    });
+
+    rl.on("line", (line) => {
+      lines.push(line);
+    });
+
+    rl.on("close", () => {
+      resolve(lines.join("\n"));
+    });
+
+    rl.on("error", (err) => {
+      reject(err);
+    });
+  });
+}

04.class/actions/deleteMemo.js

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+import { selectMemo } from "../helpers/memoHelpers.js";
+
+export async function deleteMemo(database) {
+  const memo = await selectMemo(database, "削除するメモを選んでください:");
+  if (!memo) {
+    console.log("メモが存在しません。");
+    return;
+  }
+  await database.delete(memo.id);
+  console.log("メモを削除しました。");
+}

04.class/actions/listMemos.js

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+export async function listMemos(database) {
+  const memos = await database.fetchAll();
+  if (memos.length === 0) {
+    console.log("メモが存在しません。");
+    return;
+  }
+
+  console.log("メモ一覧:");
+  memos.forEach((memo) => {
+    const firstLine = memo.content.split("\n")[0];
+    console.log(`・${firstLine}`);
+  });
+}

04.class/actions/readMemo.js

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+import { selectMemo } from "../helpers/memoHelpers.js";
+
+export async function readMemo(database) {
+  const memo = await selectMemo(database, "表示するメモを選んでください:");
+  if (!memo) {
+    console.log("メモが存在しません。");
+    return;
+  }
+  console.log(memo.content);
+}

04.class/config/settings.js

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+export const DATABASE_PATH = "db/memo.db";
+export const OPTIONS = {
+  LIST: "-l",
+  READ: "-r",
+  DELETE: "-d",
+};

04.class/db/memoDatabase.js

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+import sqlite3 from "sqlite3";
+
+export class MemoDatabase {
+  #database;
+  #databasePath;
+
+  constructor(databasePath = "db/memo.db") {
+    this.#databasePath = databasePath;
+  }
+
+  async connect() {
+    try {
+      this.#database = await this.#openDatabase(this.#databasePath);
+    } catch (err) {
+      throw err;
+    }
+  }
+
+  async createTable() {
+    try {
+      await this.#createMemosTable();
+    } catch (err) {
+      if (err.code === "SQLITE_ERROR") {
+        throw err;
+      }
+    }
+  }
+
+  insert(content) {
+    return new Promise((resolve, reject) => {
+      this.#database.run(
+        "INSERT INTO memos (content) VALUES (?)",
+        [content],
+        (err) => {
+          if (err) {
+            reject(err);
+          } else {
+            resolve();
+          }
+        },
+      );
+    });
+  }
+
+  fetchAll() {
+    return new Promise((resolve, reject) => {
+      this.#database.all(
+        "SELECT * FROM memos ORDER BY id DESC",
+        (err, rows) => {
+          if (err) {
+            reject(err);
+          } else {
+            resolve(rows);
+          }
+        },
+      );
+    });
+  }
+
+  delete(id) {
+    return new Promise((resolve, reject) => {
+      this.#database.run("DELETE FROM memos WHERE id = ?", [id], (err) => {
+        if (err) {
+          reject(err);
+        } else {
+          resolve();
+        }
+      });
+    });
+  }
+
+  #openDatabase(path) {
+    return new Promise((resolve, reject) => {
+      const db = new sqlite3.Database(path, (err) => {
+        if (err) {
+          reject(err);
+        } else {
+          resolve(db);
+        }
+      });
+    });
+  }
+
+  #createMemosTable() {
+    return new Promise((resolve, reject) => {
+      this.#database.run(
+        "CREATE TABLE IF NOT EXISTS memos (id INTEGER PRIMARY KEY AUTOINCREMENT, content TEXT NOT NULL)",
+        (err) => {
+          if (err) {
+            reject(err);
+          } else {
+            resolve();
+          }
+        },
+      );
+    });
+  }
+}

04.class/helpers/memoHelpers.js

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+import inquirer from "inquirer";
+import { ExitPromptError } from "@inquirer/core";
+
+export async function selectMemo(database, message) {
+  const memos = await database.fetchAll();
+  if (memos.length === 0) {
+    return null;
+  }
+
+  const choices = memos.map((memo) => ({
+    name: memo.content.split("\n")[0],
+    value: memo,
+  }));
+
+  try {
+    const answer = await inquirer.prompt([
+      {
+        type: "list",
+        name: "selectedMemo",
+        message,
+        choices,
+      },
+    ]);
+
+    return answer.selectedMemo;
+  } catch (error) {
+    if (error instanceof ExitPromptError) {
+      process.stdout.write("Ctrl+C/Dが入力された為処理を終了させました");
+      process.exit(0);
+    }
+  }
+}

04.class/memo.js

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+#!/usr/bin/env node
+
+import { MemoDatabase } from "./db/memoDatabase.js";
+import { DATABASE_PATH, OPTIONS } from "./config/settings.js";
+import { listMemos } from "./actions/listMemos.js";
+import { readMemo } from "./actions/readMemo.js";
+import { deleteMemo } from "./actions/deleteMemo.js";
+import { addMemo } from "./actions/addMemo.js";
+
+async function main() {
+  const memoDatabase = new MemoDatabase(DATABASE_PATH);
+
+  try {
+    await memoDatabase.connect();
+  } catch (err) {
+    if (err.code === "SQLITE_CANTOPEN") {
+      console.error(`データベースを開けません: ${err.message}`);
+    } else if (err.code === "SQLITE_NOTADB") {
+      console.error(`データベースファイルではありません: ${err.message}`);
+    } else {
+      console.error(`データベースに接続できません: ${err.message}`);
+    }
+    process.exit(1);
+  }
+
+  try {
+    await memoDatabase.createTable();
+  } catch (err) {
+    if (err.code === "SQLITE_ERROR") {
+      console.error(`テーブルを作成できません: ${err.message}`);
+    } else {
+      console.error(`エラーが発生しました: ${err.message}`);
+    }
+    process.exit(1);
+  }
+
+  const args = process.argv.slice(2);
+
+  switch (args[0]) {
+    case OPTIONS.LIST:
+      await listMemos(memoDatabase);
+      break;
+    case OPTIONS.READ:
+      await readMemo(memoDatabase);
+      break;
+    case OPTIONS.DELETE:
+      await deleteMemo(memoDatabase);
+      break;
+    default:
+      try {
+        await addMemo(memoDatabase);
+        break;
+      } catch (err) {
+        if (err.code === "ENOMEM") {
+          console.error(`システムのメモリ制限を超過しました: ${err.message}`);
+          process.exit(1);
+        }
+      }
+  }
+}
+
+main();