Lesson 14: Understanding Promises in JavaScript

Lesson Overview

In this lesson, we will learn about Promises in JavaScript, how they work, and how to use them to handle asynchronous operations.

Graphical Preview

Graphical representation of Promises will be shown here.

Code Preview

                
const myPromise = new Promise((resolve, reject) => {
    // Simulate an asynchronous operation
    setTimeout(() => {
        const success = true; // Change to false to simulate an error
        if (success) {
            resolve("Operation was successful!");
        } else {
            reject("Operation failed.");
        }
    }, 2000);
});

myPromise
    .then(result => console.log(result))
    .catch(error => console.error(error));

Lesson 14: Understanding Promises in JavaScript

Lesson Overview

In this lesson, we will learn about Promises in JavaScript, how they work, and how to use them to handle asynchronous operations.

Graphical Preview

Graphical representation of Promises will be shown here.

Code Preview

                
const myPromise = new Promise((resolve, reject) => {
    setTimeout(() => {
        const success = true;
        if (success) {
            resolve("Operation was successful!");
        } else {
            reject("Operation failed.");
        }
    }, 2000);
});

myPromise
    .then(result => console.log(result))
    .catch(error => console.error(error));

`; const blob = new Blob([htmlContent], { type: 'text/html' }); const url = URL.createObjectURL(blob); const a = document.createElement('a'); a.href = url; a.download = 'lesson14.html'; a.click(); URL.revokeObjectURL(url); }); document.getElementById('download-js').addEventListener('click', function() { const jsContent = `const myPromise = new Promise((resolve, reject) => { setTimeout(() => { const success = true; if (success) { resolve("Operation was successful!"); } else { reject("Operation failed."); } }, 2000); }); myPromise .then(result => console.log(result)) .catch(error => console.error(error));`; const blob = new Blob([jsContent], { type: 'application/javascript' }); const url = URL.createObjectURL(blob); const a = document.createElement('a'); a.href = url; a.download = 'lesson14.js'; a.click(); URL.revokeObjectURL(url); });