Using a filename as a function input
While creating a new function that reads the file, passing the filename as an argument is not considered best practice and might have negative effects such as making it difficult to write test cases for a variety of criteria. Suppose we want to implement a function to count the number of empty lines in a…
Konika SitoulaIgnoring how defer arguments are evaluated
In order to understand how arguments are processed using the defer keyword, let’s consider a specific example. Suppose we have a function that needs to execute two other functions, called foo and bar. Additionally, this function needs to handle some status information related to its execution. We can use the defer keyword to ensure that…
Misunderstanding variable scope in JavaScript
In this post, we are going to understand variable scope and difference between var, let and const keywords in javascript. Variable scope is tricky concept for new developers., especially in javascript. Most of beginner developers make common mistake like defining the variable inside the function and expecting it to access outside the function. Understanding var,…
Suresh ThapaUsing index as a key in React (anti-pattern)
What are lists in React ? Lists are used to display data which are similar in ordered format . Often they have same type i.e an array of similar kind of data rendered into a list tag using some version of for loop. How does react render lists? DOM Before we learn how react renders lists…
Bishal SinghObject references and copying
One of the fundamental differences of objects versus primitives is that objects are stored and copied “by reference”, whereas primitive values: strings, numbers, booleans, etc – are always copied “as a whole value”. That’s easy to understand if we look a bit under the hood of what happens when we copy a value. Let’s start…
Introducing constructors
If we need to create multiple object of same shape then one of the way to define the shape of is by using the function. we have to create an empty object, initialize it, and return it. A better way is to use a constructor. A constructor is just a function called using the new keyword. When…
Scheduling: setTimeout and setInterval
We may decide to execute a function not right now, but at a certain time later. That’s called “scheduling a call”. There are two methods for it: These methods are not a part of JavaScript specification. But most environments have the internal scheduler and provide these methods. In particular, they are supported in all browsers…
Utility Types in TypeScript
What are utility Types? In TypeScript, utility types are built-in types that allow you to manipulate and transform existing types. They can be used to extract, exclude, or modify the properties of an existing type, or to create a new type based on an existing one. TypeScript provides several utility types to facilitate common type…