Intro to Asynchronous JavaScript

Asynchronous

• A technique that enables your program to start a potentially long-running task and still be able to be responsible to other events while that task runs, rather than having to wait until that task has finished
• Once the task has finished, your program is presented with the result

• Event handlers are a form of asynchronous programming = you provide a function (the event handler) that will be called, not right away, but whenever the event happens
  • DOM (Document Object Model)
  • https://developer.mozilla.org/en-US/docs/Learn_web_development/Core/Scripting/Events
• Event handler is a particular type of callback (function passed into another function)
  • Callback Functions
  • But modern asynchronous APIs don’t use callbacks, instead the foundation is Promise
  • Promises