Tips on writing better JavaScript...

Dealing with asynchronous actions in JavaScript using callbacks, promises, and async/await...

Using JavaScript's fetch api instead of RxJS observable in an Angular data service.

In this blog post I explain how to secure an API with OAuth 2.0 authorization framework as well as implementing changes in a Web app/page to allow users access to that API. This implementation uses JavaScript in frontend and backend (Node.js)...

In this post I show how to throttle a function using setInterval and how to debounce a function using setTimeout.

If you have an input field of type="date" and wish to set it by default to current date you can use below function...

If you want to build a SPA (single page application) from a MPA (multi page application) you don't always need a giant framework. What you need mainly is to set an event handler on your links to disable their default behaviour...

If you have some markup as string and wish to add it to a HTML page via JavaScript, the old way was...

Did you know that a HTML anchor element can be treated as a Location object? This means similar to how you can use window.location to read or write different parts of a URL, you can do the same with an anchor element. For example if you have a link like this:

<a id="myLink" href="https://mydomain/products.html?category=clothing#productName">test</a>

You can get the value of hash in this way:

const hash = document.getElementById('myLink').hash.substring(1); // returns productName

You can use different properties of Location object on an anchor element and same as with window.location you can both read and write these properties. For example to get the value of category from previous link you can use this:

const params = document.getElementById('myLink').search;
const category = new URLSearchParams(params).get('category'); // clothing

For more info see: https://developer.mozilla.org/en-US/docs/Web/API/Location

Sometimes you need to display data that you fetch from backend in a custom order in frontend. The following snippet shows how to order objects in our array using a custom order defined in another array. Note that to avoid mutation we need to use WEB API's structuredClone() method instead of spread syntax (...) as spread syntax only does a shallow copy of array items and hence won't be able to clone objects inside an array.

const myArray = [
  {name: 'firstname', value: 'Tom'},
  {name: 'age', value: 61},
  {name: 'lastname', value: 'Cruise'}
];
const mySortOrder = ['firstname', 'lastname', 'age'];
const sortArray = (myArray, mySortOrder) => {
  myArray.sort((a, b) => {
    const indexA = mySortOrder.indexOf(a.name);
    const indexB = mySortOrder.indexOf(b.name);
    return indexA - indexB;
  });
  return myArray;
}
const sortedArray = sortArray(structuredClone(myArray), mySortOrder);
console.log(sortedArray);