lsflexdb

lsflexdb is a lightweight library for managing data in localStorage, allowing you to create tables and perform basic CRUD operations with ease.

Features

• Create tables in localStorage
• Automatic or manual data saving
• Support for basic CRUD operations (Create, Read, Update, Delete)
• Data filtering and ordering capabilities
• Designed for use in both browsers and Angular projects

Installation

Install the package using the following command:

npm install lsflexdb

Usage

First, import the library.

Angular

import lsflexDB from 'lsflexdb';

Browser

Include the script in your HTML file:

<script src="path/to/lsflexdb.js"></script>

Create Database

Create an instance of the database:

// Create a new database instance
const lsDB_blog = new lsflexDB("blog", { auto_save: true });

Methods

1. create(tableName, structure)

Creates a new table with the specified structure.

• tableName: The name of the table
• structure: An object defining the table's columns

lsDB_blog.create("users", {
    username: "",
    password: "",
    is_active: 0
});

2. select(where)

Retrieves data from the table with optional filtering.

• where (optional): An object specifying filter conditions

// Get all users
let allUsers = lsDB_blog.users.select();

// Filter users based on conditions
let activeUsers = lsDB_blog.users.select({ is_active: 1 });

3. insert(values, options)

Adds new data to the table.

• values: An object containing the new data
• options (optional): Settings for saving, { save: true | false }

lsDB_blog.users.insert({
    username: "admin",
    password: "12345",
    is_active: 1
}, { save: true });

4. update(data, where, options)

Updates existing data in the table.

• data: An object containing the new values
• where: Filter conditions for selecting rows to update
• options (optional): Settings for saving, { save: true | false }

lsDB_blog.users.update(
    { is_active: 0 },
    { username: "admin" },
    { save: true }
);

5. delete(where, options)

Removes data from the table.

• where: Filter conditions for selecting rows to delete
• options (optional): Settings for saving, { save: true | false }

lsDB_blog.users.delete({ username: "admin" }, { save: false });

6. save()

Manually saves the data to localStorage.

lsDB_blog.users.save();

Using Different where Conditions

The where parameter supports various conditions for filtering data:

1. Basic Equality

   // Select users with a specific email
   let userByEmail = lsDB_blog.users.select({ email: "[email protected]" });

2. Comparison Operators

   • > (greater than), >= (greater than or equal), < (less than), <= (less than or equal)

   // Select users with user_id greater than 200
   let usersAbove200 = lsDB_blog.users.select({ "user_id[>]": 200 });
   
   // Select users with user_id less than or equal to 300
   let usersBelow300 = lsDB_blog.users.select({ "user_id[<=]": 300 });

3. Not Equal

   // Select users who are not active
   let inactiveUsers = lsDB_blog.users.select({ "is_active[!]": 1 });

4. Pattern Matching

   • LIKE operator using [~]

   // Select users where city contains 'lon'
   let usersInLondon = lsDB_blog.users.select({ "city[~]": "lon" });

5. Between

   // Select users with age between 20 and 30
   let usersIn20s = lsDB_blog.users.select({ "age[<>]": [20, 30] });
   
   // Select users with age not between 40 and 50
   let usersOutside40s = lsDB_blog.users.select({ "age[><]": [40, 50] });

6. In Array

   // Select users with specific user_ids
   let specificUsers = lsDB_blog.users.select({ user_id: [2, 123, 234, 54] });
   
   // Select users with specific emails
   let specificEmails = lsDB_blog.users.select({ email: ["[email protected]", "[email protected]", "[email protected]"] });

7. Custom Filtering Function

   // Use a custom function to filter users
   let customFilteredUsers = lsDB_blog.users.select({
       age: (value) => value > 20 && value < 50
   });

Complete Example

import { lsflexDB } from 'lsflexdb';

// Create the database
const lsDB_blog = new lsflexDB("blog", { auto_save: true });

// Create the 'users' table
lsDB_blog.create("users", {
    username: "",
    password: "",
    is_active: 0
});

// Insert a new user
lsDB_blog.users.insert({
    username: "admin",
    password: "12345",
    is_active: 1
});

// Update the user's status
lsDB_blog.users.update(
    { is_active: 0 },
    { username: "admin" }
);

// Get active users
let activeUsers = lsDB_blog.users.select({ is_active: 1 });

// Delete the user
lsDB_blog.users.delete({ username: "admin" });