IndexedDBManager Documentation

Overview

The IndexedDBManager class is a tool for managing IndexedDB databases in JavaScript. This class provides basic CRUD (Create, Read, Update, Delete) operations and supports dynamically creating and managing indexes and fields. Additionally, it allows you to easily upgrade the database structure using versioning.

Constructor

constructor(dbName, storeName, fields = [])

• Description: The constructor of the IndexedDBManager class, which creates a database with the provided name.
• Parameters:
  • dbName: The name of the database (data type: string).
  • storeName: The name of the object store in the database (data type: string).
  • fields: An array of objects that define the fields of the database. Each object contains name (the field name) and unique (whether the field is unique or not). This parameter is optional and defaults to an empty array.
• Returns: Creates an instance of the IndexedDBManager class.

Example:

const fields = [
  { name: "title", unique: false },
  { name: "author", unique: false },
  { name: "year", unique: false },
  { name: "publisher", unique: false }
];

const dbManager = new IndexedDBManager("LibraryDB", "books", fields);

Methods

openDB(version = 1)

• Description: Opens the database with the specified version, or creates it if necessary. If the database already exists and a new version is provided, the onupgradeneeded method will be triggered.
• Parameters:
  • version (optional): The database version, which defaults to 1.
• Returns: A Promise that, if successful, returns a message "Database opened successfully". If an error occurs, it returns "Error opening database".

Example:

dbManager.openDB(1)  // Opening the database with version 1
  .then((message) => console.log(message))
  .catch((error) => console.error(error));

addItem(item)

• Description: Adds a new item to the database.
• Parameters:
  • item: The object you want to store in the database. This object must contain data that corresponds to the table's fields.
• Returns: A Promise that, if successful, returns the message "Item added successfully". If an error occurs, it returns "Error adding item".

Example:

const newBook = {
  title: "Clean Code",
  author: "Robert C. Martin",
  year: 2008,
  publisher: "Prentice Hall"
};

dbManager.addItem(newBook)
  .then((message) => console.log(message))
  .catch((error) => console.error(error));

getAllItems()

• Description: Retrieves all the items in the database.
• Parameters: None.
• Returns: A Promise that, if successful, returns the items as an array of objects. If an error occurs, it returns "Error retrieving items".

Example:

dbManager.getAllItems()
  .then((items) => console.log(items))
  .catch((error) => console.error(error));

getItemsByIndex(indexName, value)

• Description: Searches for items based on an index.
• Parameters:
  • indexName: The name of the index you want to search by (data type: string).
  • value: The value you want to search for in the index (data type: any).
• Returns: A Promise that, if successful, returns the items as an array of objects. If an error occurs, it returns "Error retrieving items by index".

Example:

dbManager.getItemsByIndex("publisher", "Prentice Hall")
  .then((items) => console.log(items))
  .catch((error) => console.error(error));

updateItem(id, updatedItem)

• Description: Updates an item with a specified ID.
• Parameters:
  • id: The ID of the item you want to update (data type: number).
  • updatedItem: The object containing the new data (data type: object).
• Returns: A Promise that, if successful, returns the message "Item updated successfully". If an error occurs, it returns "Error updating item".

Example:

const updatedBook = {
  year: 2009
};

dbManager.updateItem(1, updatedBook)
  .then((message) => console.log(message))
  .catch((error) => console.error(error));

deleteItem(id)

• Description: Deletes an item with a specified ID.
• Parameters:
  • id: The ID of the item you want to delete (data type: number).
• Returns: A Promise that, if successful, returns the message "Item deleted successfully". If an error occurs, it returns "Error deleting item".

Example:

dbManager.deleteItem(1)
  .then((message) => console.log(message))
  .catch((error) => console.error(error));

listIndexes()

• Description: Retrieves the indexes in the object store.
• Parameters: None.
• Returns: A Promise that, if successful, returns an array of index names. If no indexes are found, it returns "No indexes found".

Example:

dbManager.listIndexes()
  .then((indexes) => console.log("Indexes:", indexes))
  .catch((error) => console.error(error));

checkFieldExists(fieldName)

• Description: Checks whether a specific field (index) exists in the database.
• Parameters:
  • fieldName: The name of the field you want to check (data type: string).
• Returns: A Promise that returns true if the field exists, and false if it does not.

Example:

dbManager.checkFieldExists("publisher")
  .then((exists) => {
    if (exists) {
      console.log("Field exists");
    } else {
      console.log("Field does not exist");
    }
  })
  .catch((error) => console.error(error));

Summary

The IndexedDBManager class is a useful tool for managing and interacting with IndexedDB databases. You can use it for CRUD operations, adding indexes, managing the database schema, and making structural changes dynamically. This class also supports versioning, so you can easily implement changes to the database structure.

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