JavaScript/TypeScript Testing a function specified in callback that cannot be triggered in test
Don't you have a good idea to write a test of the logic specified in a callback function? Isn't it possible to control t...
JavaScript/TypeScript
JavaScript/TypeScript 
JavaScript/TypeScript How to Restrict Possible String Arguments
I want to limit the possible string arguments. How can I do it? This article is for you. I will show 4 ways to do it. Th...
JavaScript/TypeScript Define array with multiple types in TypeScript
Union type or tuple is useful to define multiple types in an array. It shows how to define it and use cases. However, if there are multiple types in an array, it's harder to handle the difference. Using an interface is often a better choice.
JavaScript/TypeScript How to implement Node-RED node in TypeScript
The official site describes how to implement our own node in JavaScript. However, I don't find a page for TypeScript. I'...
JavaScript/TypeScript Complete Class Guide in TypeScript
Class is one of keys to be familir with Object Oriented Programming (OOP). Multiple variables and functions are in the s...
JavaScript/TypeScript TypeScript Bracket notation causes index signature error
TypeScript shows an error when we access an object with brackets like obj to get the value. How can we safely resolve it...
JavaScript/TypeScript 8 ways to remove duplicates from Array in TypeScript
This page shows 8 ways to remove duplicates from an array. It also compares the performance to be useful to decide which one to use for your case. It also covers the case where the element is object.
JavaScript/TypeScript How to generate Number Range Array in TypeScript
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.
JavaScript/TypeScript String concat in JavaScript Performance Comparison
JavaScript offers several ways to concatenate strings. Let's learn how to concatenate strings and which one is the best ...
JavaScript/TypeScript Making your code more abstract by Generics in Typescript
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...