TypeScript shows an error when we access an object with brackets like obj to get the value. How can we safely resolve it...

This post shows how to implement range function. It supports not only integer type but also floating type as well as ascending and descending order. Even if you need too big/small numbers, it can handle them by log notation.

Our code gets more readable if we make it more abstract. We don't need to know how they work as long as it works. Many u...

We often need to build similar structures in different objects. Some functions require the same variables but want to ha...

Null check in many places is tedious. This post shows you how to reduce such work in a nice way.

Explains how to get value by key, get key by value, and use an enum as an object key. Some functions don't behave as expected when an enum has number values or mixed type data. All enum-related solutions are on this page.

The spread operator (three dots) is used to copy an array and expand an array to pass the values to another object or function parameters. It can also be used as rest parameters in a function to indicate that the function can take as many arguments as you want. The spread operator is handled as a shallow copy. Therefore you need to be careful if you use it for an object that has objects in the property list.