js-series/16-LocalStorage-SessionStorage-&-JSON.html at main · jdcodebase/js-series · GitHub

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<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>16-LocalStorage-SessionStorage-&-JSON</title>
  </head>
  <body>
    <script>
      /* ================================
         LOCAL STORAGE – BASIC EXAMPLE
         ================================ */

      // Save data in localStorage (key-value pair)
      localStorage.setItem("name", "JD");

      // Get data from localStorage
      let myName = localStorage.getItem("name");
      console.log(myName); // Output: JD

      // Remove single item from localStorage
      // localStorage.removeItem("name");

      // Clear all localStorage data
      // localStorage.clear();

      /* ================================
         SESSION STORAGE – BASIC EXAMPLE
         ================================ */

      // Save data in sessionStorage
      // This data will be removed when the browser tab is closed
      sessionStorage.setItem("city", "Delhi");

      /* ================================
         STORING OBJECT USING JSON
         ================================ */

      // JavaScript object
      let user = {
        name: "JD",
        age: 25,
      };

      // Convert object to JSON string before saving
      localStorage.setItem("user", JSON.stringify(user));

      /* ================================
         STORING ARRAY USING JSON
         ================================ */

      // JavaScript array
      let fruits = ["apple", "pineapple"];

      // Convert array to JSON string and save
      localStorage.setItem("fruitsData", JSON.stringify(fruits));

      // Get JSON string from localStorage
      let fruitsData = localStorage.getItem("fruitsData");
      console.log(fruitsData); // String format

      /* ================================
         JSON.parse() – CONVERT BACK
         ================================ */

      // Get user data as string
      let userData = localStorage.getItem("user");
      console.log(userData); // JSON string

      // Convert JSON string back to object
      console.log(JSON.parse(userData));

      /* ================================
         THEME SAVE EXAMPLE
         ================================ */

      // Save theme preference
      localStorage.setItem("theme", "dark");

      // Get theme from localStorage
      let theme = localStorage.getItem("theme");

      // Apply theme to body
      document.body.className = theme;

      /* ================================
         TODO LIST STORAGE EXAMPLE
         ================================ */

      // Todo list array
      let todoList = ["Learn JS", "Practice Code"];

      // Save todo list using JSON
      localStorage.setItem("todos", JSON.stringify(todoList));

      // Get todos from localStorage
      // If no data exists, use empty array
      let savedTodos = JSON.parse(localStorage.getItem("todos")) || [];

      console.log(savedTodos);
    </script>
  </body>
</html>