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Exercise 27: To-Do List with localStorage

Create a functional to-do list in JavaScript that saves the information to localStorage, even after closing the browser. The main goal is to learn how to store and manage a to-do list in JavaScript.localStoragePractice usingJSON.stringify and JSON.parseto store and retrieve arrays of objects.

Activity​

  1. Create a functionagregarTarea(tarea)that receives a task (as a string) and adds the task to a task list inlocalStorage.

  2. If the task list already exists inlocalStorageAdd the new task to the existing array. If it doesn't exist, create a new array with the first task.

  3. Save the updated task list inlocalStorage4. Create a functionmostrarTareas()that retrieves the to-do list fromlocalStorageand display each task in the console.

  4. Call both functions to add and display some tasks.

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Solution​

Step 1: Create the index.html file​

HTML
<!DOCTYPE html>
<html lang="es">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Lista de Tareas con localStorage</title>
  </head>
  <body>
    <h1>Ejercicio 27: Lista de Tareas con localStorage</h1>
    <p>Los cambios se muestran en consola.</p>
    <script src="script.js"></script>
  </body>
</html>

Step 2: Write the code in script.js​

JavaScript
// Función para agregar tareas al localStorage
function agregarTarea(tarea) {
  // Paso 1: Verificar si ya existe una lista de tareas
  let tareas = JSON.parse(localStorage.getItem("tareas")) || [];

  // Paso 2: Agregar la nueva tarea al array de tareas
  tareas.push(tarea);

  // Paso 3: Guardar la lista actualizada en localStorage
  localStorage.setItem("tareas", JSON.stringify(tareas));
}

// Función para mostrar las tareas guardadas en localStorage
function mostrarTareas() {
  // Paso 4: Recuperar la lista de tareas desde localStorage
  const tareas = JSON.parse(localStorage.getItem("tareas")) || [];

  // Paso 5: Mostrar cada tarea en la consola
  console.log("Lista de tareas:");
  tareas.forEach((tarea, index) => {
    console.log(`${index + 1}. ${tarea}`);
  });
}

// Llamadas de ejemplo
agregarTarea("Aprender JavaScript");
agregarTarea("Practicar HTML y CSS");
agregarTarea("Estudiar localStorage");

mostrarTareas();
info

🔎Review the following sections where you will find more information on this topic:

Local Storage in JavaScript

Control instructions in JavaScript

Array methods in JavaScript