Asynchronous Javascript from A to Z

Explore how asynchronous programming in modern JavaScript lets the program continue other tasks while waiting for operations to complete, with examples like network requests and the promise object.

Explore how a promise represents the eventual outcome of an asynchronous operation, with pending, fulfilled, or rejected states, and learn to handle both fulfilled results and rejections.

construct a new promise with the promise constructor, using an executor function that takes resolve and reject to settle the promise as fulfilled or rejected, then log the result.

Learn to consume promises returned by asynchronous operations using setTimeout, observe promise states from pending to settled, and simulate asynchronous flows with delays and the event loop.

Master how to use the then method to attach success and failure handlers to promises, handle fulfills and rejecting, and recognize that then returns a new promise for chaining.

Learn how to use promises to handle success and failure with onFulFilled and onRejected, chaining then handlers to log resolved values or rejection reasons, and simulate an inventory check.

Learn how to use catch with promises to separate success and failure handlers, compare then and catch, and write readable promise chains that handle rejection clearly.

Learn to chain multiple promises in asynchronous javascript by composing promises, returning promises in then handlers, and handling errors with catch while simulating inventory checks, payments, and shipping.

Learn to avoid common mistakes in promise composition, including nested promises and failing to return promises, by chaining with then for clearer, readable async code.

Learn to run multiple promises concurrently with Promise.all, which resolves when all checks succeed and rejects fast if any fails, demonstrated with availability checks for sunglasses, bands, and bags.

Explain how promises move between states and are settled when they resolve or reject, and construct them with the new keyword, an executor, and then and catch for composition.

Explore how JavaScript handles asynchronous actions with the event loop, using callbacks, promises, and async/await to write readable, scalable code that reads and writes two files in order.

Learn how the async keyword declares async functions, how to define them by function or expression, and how these functions return undefined or promises you handle with then and catch.

Master the await operator within async functions to pause execution until a promise resolves. Learn to simulate database data with setTimeout, observe resolved values, and distinguish awaited from non-awaited code.

Explore how async functions control promise resolution with and without await, including how await yields the resolved value. Refactor get beans to ensure proper logging and correct behavior.

Learn to manage dependent promises with then chaining and async/await, and see an async function make beans that uses show for beans, soak the beans, and cook the beans.

Handle errors in JavaScript with try catch and async/await to catch synchronous and asynchronous errors, using promises to resolve or reject and log outcomes.

Handle independent promises with concurrency in asynchronous javascript from a to z by constructing promises without wait, awaiting results, and running them simultaneously.

Learn how to use Promise.all to run multiple promises concurrently, returning an array of results when all resolve, with fast failure if any rejects.

Review async/await syntax by declaring async functions and using await to pause until promises resolve, employ try-catch for error handling, and leverage concurrency by running asynchronous actions concurrently whenever possible.