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Introducing Promises in JavaScript
A step-by-step guide to promises for beginners.
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If you would like to see a video walkthrough of this article it is available below.
What is asynchronous?
Usually, when you hear about promises in JavaScript, you also hear the word asynchronous. What is asynchronous? First, we have synchronous which means something which is performed step by step. When you are walking you put one foot in front of the other and you don’t do both at the same time unless you are jumping! Another example is waiting for a kettle to boil before you make a cup of tea. Asynchronous on the other hand means you can do other things in the background without everything stopping and waiting. It’s a bit like saying you might watch some tv whilst you wait for the kettle to boil as opposed to standing and staring at the kettle waiting on it.
JavaScript is what we call a single-threaded language, this means only one thing can happen at once and at one time. Asynchronous JavaScript is the way in which background tasks (such as requests to…