Sometimes you want to check if a given date represents “yesterday”, the previous day of today. For example, this use-case appears in UI elements where you’re showing relative dates like “yesterday” instead of the YYYY-MM-DD format. This tutorial shows you how to detect whether a given date is yesterday! …

Formatting dates is a common task in application. Displaying due dates or birthdays is always connected to dates. A typical formatting for readable dates is the YYYY-MM-DD format. This tutorial shows you how to format a JavaScript date in the YYYY-MM-DD format. {{outline}} Formatting JavaScript Dates in YYYY-MM-DD Formatting dates …

Large numbers are hard to read. For example, what about “2014010167“? Is it 20 million, 200 million, or 2 billion? Yeah, we can’t read that number either and need to concentrate. What about “2014010_167”? Much better! JavaScript shipped a new feature called “numeric separator” to improve readability on …

You can dynamically compose objects in JavaScript. You may add a property depending on a configuration or not. For example, when creating a database model you may allow users to configure whether to add or skip timestamps like createdOn and updatedOn. Model instances won’t have timestamps if a user …

In some situations you want to check if a given value is an array (or something else). This may be a required check in your code when allowing single items or an array of items as a method argument. This tutorial walks you through the pitfalls of using typeof and …

Sometimes you need to check for the type of a variable before moving on with any processing. For example, you may want to validate a value to be an object before merging its properties with another object. This tutorial shows you how to confidently check whether a given value is …

JavaScript introduced the destructuring assignment back in 2015. The destructuring assignment is a way to unpack properties of an object or items from arrays into variables using a syntax that looks like objects or arrays. This tutorial shows you how to use nested destructuring in JavaScript. {{outline}} Using Nested Destructuring …

Randomizing items should lead to an even distribution of available elements. For example, a coding error lead to an uneven distribution in Microsoft’s browser choice. This is something you want to avoid when shuffling items randomly. This tutorial shows you how to randomize the characters of a string using …