From f756963dbc53d58103fc936e05730d0d65cc46cf Mon Sep 17 00:00:00 2001
From: Yasmika Saubhagya <yashtricksz@gmail.com>
Date: Mon, 12 Apr 2021 20:51:11 +0530
Subject: [PATCH] Improve with more functionality

---
 .gitignore               |  2 +
 src/dropdb.js            | 80 ++++++++++++++++++++++++++++++++++++----
 src/util/file-process.js | 37 +++++--------------
 3 files changed, 85 insertions(+), 34 deletions(-)

diff --git a/.gitignore b/.gitignore
index 69d9865..dcdb40b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,3 +2,5 @@ node_modules/
 db/
 package-lock.json
 app.js
+db.json
+.vscode
diff --git a/src/dropdb.js b/src/dropdb.js
index db83b43..10d9901 100644
--- a/src/dropdb.js
+++ b/src/dropdb.js
@@ -1,14 +1,12 @@
 const { v4 } = require("uuid");
 const osPath = require("path");
+const EventEmitter = require("events");
 
-const {
-  readFromFile,
-  readFromFileCb,
-  writeToFile,
-} = require("./util/file-process");
+const { readFromFile, writeToFile } = require("./util/file-process");
 
-class DropDB {
+class DropDB extends EventEmitter {
   constructor(path) {
+    super();
     if (path) {
       if (typeof path !== "string")
         throw new TypeError("DROPDB: Path should be a string value");
@@ -17,8 +15,21 @@ class DropDB {
       this._path = osPath.join(__dirname, "/db.json");
     }
 
+    const initDB = async () => {
+      try {
+        try {
+          await readFromFile(this._path);
+        } catch (err) {
+          if (err.code === "ENOENT") await writeToFile(this._path, []);
+        }
+      } catch (err) {
+        throw new Error("DROPDB: Init database failed");
+      }
+      this.emit("ready");
+    };
+
     // Clear the file with [] if no data is available
-    readFromFileCb(this._path, () => {});
+    initDB();
   }
 
   set path(path) {
@@ -157,6 +168,61 @@ class DropDB {
     }
   }
 
+  async deleteById(path, id, cb) {
+    if (cb) {
+      if (typeof cb !== "function")
+        throw new TypeError("DROPDB: Callback should be a function");
+    }
+
+    try {
+      if (typeof path !== "string")
+        throw new TypeError("DROPDB: Path should be string value");
+      if (typeof id !== "string")
+        throw new TypeError("DROPDB: Id should be passed as data");
+
+      const dataArray = await readFromFile(this._path);
+
+      let pathData = null;
+      let pathDataIndex = 0;
+      for (let item of dataArray) {
+        if (item[path]) {
+          pathData = item[path];
+          break;
+        }
+        pathDataIndex++;
+      }
+
+      if (pathData !== null) {
+        let dataItem = null;
+        let dataItemIndex = 0;
+        for (let item of pathData) {
+          if (item.id === id) {
+            dataItem = item;
+            break;
+          }
+          dataItemIndex++;
+        }
+
+        // Ready to be removed the data from db
+        if (dataItem) {
+          dataArray[pathDataIndex][path].splice(
+            dataItemIndex,
+            dataItemIndex + 1
+          );
+
+          await writeToFile(this._path, dataArray);
+          if (cb) cb(null, dataItem);
+        } else {
+          if (cb) cb(null, null);
+        }
+      } else {
+        if (cb) cb(null, null);
+      }
+    } catch (err) {
+      if (cb) cb(err);
+    }
+  }
+
   async getPathData(path, cb) {
     if (typeof cb !== "function")
       throw new TypeError("DROPDB: Callback should be a function");
diff --git a/src/util/file-process.js b/src/util/file-process.js
index 2873e8e..7bfcce1 100644
--- a/src/util/file-process.js
+++ b/src/util/file-process.js
@@ -3,8 +3,15 @@ const fs = require("fs");
 const readFromFile = (path) => {
   return new Promise((resolve, reject) => {
     fs.readFile(path, (err, data) => {
-      if (err) reject(new Error("DROPDB: Could not retrieve data"));
-      resolve(JSON.parse(data));
+      if (err) {
+        if (err.code === "ENOENT") {
+          const error = new Error("DROPDB: Could not read data");
+          error.code = "ENOENT";
+          reject(error);
+        } else {
+          reject(new Error("DROPDB: Could not read data"));
+        }
+      } else resolve(JSON.parse(data));
     });
   });
 };
@@ -13,36 +20,12 @@ const writeToFile = (path, data) => {
   return new Promise((resolve, reject) => {
     fs.writeFile(path, JSON.stringify(data), (err) => {
       if (err) reject(new Error("DROPDB: Could not write data"));
-      resolve(true);
+      else resolve(true);
     });
   });
 };
 
-const readFromFileCb = (path, cb) => {
-  fs.readFile(path, (err, data) => {
-    if (err) {
-      // Write with empty [] if no file exists
-      if (err.code === "ENOENT") {
-        writeToFileCb(path, [], () => readFromFileCb(path, cb));
-      } else {
-        throw new Error("DROPDB: Could not read data");
-      }
-    } else {
-      cb(JSON.parse(data));
-    }
-  });
-};
-
-const writeToFileCb = (path, data, cb) => {
-  fs.writeFile(path, JSON.stringify(data), (err) => {
-    if (err) throw new Error("DROPDB: Could not write data");
-    else cb();
-  });
-};
-
 module.exports = {
   readFromFile,
   writeToFile,
-  readFromFileCb,
-  writeToFileCb,
 };